I suppose only a Texan could love any of the long drives in this state. It's about 800 miles from Beaumont to El Paso, or from Amarillo to Brownsville. "The sun has risen, the sun has set, and we ain't out of Texas yet!" There is a lot of pretty scenery throughout the state, but there are also some awfully long and dull stretches with not a lot going on. You really should avoid the Interstates, country roads are much more enjoyable.
 
We recently drove from Dallas to Quitequa (pronounced "Kitty-kway") southeast of Amarillo, to go camping at Caprock Canyons state park. Most of the drive was uninteresting, but eventually you get to the gorgeous escarpments and canyons, and countless wildflowers in the spring. Folks who grew up with mountains and oceans might not be impressed, but the vast prairies have a special kind of beauty for us.

um.......
 
who's David Beckham?

Here's mine starting from Philadelphia (kind of long)
 
Headed west on I-76/80 to Chicago, crossed the Mississippi then jumped on I-90 W from Minnesota (didn't see another car on the highway for over two hours during one period). Minnesota was nothing but corn fields. Took I-80 through Sioux Falls SD, Badlands Nation Park and stopped to see Mt Rushmore near Rapid City. I-90 turned northwest up through through Gilette & Sheridan Wyoming and becomes very mountainous and scenic near the Little Big Horn range. We then entered Montana which has must see terrain. Speed limits are pointless and you can coast downhill after every climb without even touching the gas. You'll even see bison grazing about in a few pastures along the road. Crossed the Continental Divide near Butte and rolled briefly though the northern tip of Idaho. Very scenic in this section before you get into Spokane, Washington. I was surprised by the landscape in Washington- dense forrests and big mountains. Eventually, we got to Seattle and took I-5 none stop all the way down to LA. We saw Mt Shasta for what seemed like forever from Oregan and Northern Cal. Took I-15 to Vegas and took Rt 89 down to Zion National Park in route to the Grand Cayon. This road is not for the faint of heart but the scenery is to die for. We then proceeded north through Utah to I-70 E and made it to Colorado. We were so high up near Loveland Pass (Eisenhower Tunnel) that bags of junk food popped from the lack of air pressure at elevation. Riding along the Colorado river and seeing freight trains down in the valleys kept our interests. The ride from Denver through Kansas was pretty boring. Missouri wasn't much better and we got through Indiana, Ohio and finally back to Pennsylvania.
 
Sorry for the length but this was coast to coast and back. I recommened everyone see Montana and Wyoming. Killer views and have yourself a Bison burger or buffalo dog along the way
 
Overnight stays were: South Bend Indiana, Sioux Falls SD, Gilette, WY, Spokane WA, Olympia WA, Las Vegas NV, Panguitch UT, Colby KS, Indianapolis IN and back home. BTW, this was done in a rental Chevy Astro and few years back. I plan to make a similar trip in '09. Karl, I'll email you some pics after work and I can dig them out and scan 'em. (pre digital camera era).

Best roadtrip...from Munich, Germany to Nice France in my new 330i. I avoided toll roads and took backroads through the Swiss Alps. Imagine two lane roads, sheer cliffs and snow-packed mountains while running a GPS that shows the road's layout. God that was a blast. Hitting the Italian toll roads kicked butt too as I skirted the Mediterranean at 110+ mph- dashing through tunnels and alongside the coastline as if I were living out Gran Turismo.
 
The drive from Avignon, France to Munich, Germany was my second favorite. It's over 600 miles and the trip took me less than 8 hours, including stops for gas, food (lunch), etc. I cruised at over 140 mph in my BMW for long stretches of my drive on the AutoBahn.

I agree with the assessment of Texas driving above. There are long, boring stretches all over the state, but you'll get treated in some locations. Driving near places like Fredericksburg in the springtime is usually great. Rolling hills and lots of wildflowers. If you must traverse the really empty parts of Texas, doing part of the driving at night helps. Less heat, and as you're often so far from city lights, absolutely brilliant starry skies. You might just pull over a gaze for a while.
 
Other thoughts:
-Going-to-the-Sun Road in Glacier National Park, MT, is a spectacular drive, especially on a sunny day.
 
-Driving I-65 through Kentucky is very nice in some areas
 
-The Blue Ridge Parkway and Skyline Drive in the fall.

My favorite trips are on the short side. Here's one I get to do a couple of times a year: San Diego to Palm Desert "the back way". I'm going to violate the even-odd rules for east-west/north-south. I-15 North to 79 East to 371 North to 74 East and down into the desert on really good twisties with great views. The scenery goes from standard freeway on I-15, to suburbia on 79, to country 2-lane on 79 through 371. On 74, you get into mountain roads with trees and descend through a moonscape of rocks into the desert. It's just the right length at 2 hours (no need for potty breaks even with the kids on board).
 
Other trips I like are I-8 east to 79 (Sunrise Highway) which you can take to 78 through Julian (a little town that gets snow in the winter) onto 76 and up to Palomar Mountain. That can be a pretty full day of driving, but is lots of fun.
 
Good Topic, Karl! Happy Motoring.

My favorite road trip would have to be from Orange County, where I live, up to San Fran by taking PCH (HWY 1). The only iffy part of the trip, is having to go straight through LA, but after that its serene beauty all the way. First there is Santa Barbara, then Pismo Beach (I usually stay 1 night even though its only 2.5 hrs from OC). following Pismo is Hearst castle and an elephant seal beach. Then, the highlight of the trip, the most scenic part of PCH winding around with cliffs on one side, and crashing waves 30 ft below on the other, (I would recommend stopping at most of the turnoffs). Once through there, there is Monterey (I usually stay another night or two). From Monterey its straight up to San Francisco. PCH continues up through Oregon and up to Seattle, also extremely beautiful, but too much driving for me.

Twice, my family and I have taken a two-day (each way) journey from the Nashville, TN area to northern Vermont to visit family. One year it was around Labor Day, the other was early July. Both trips were breathtakingly beautiful most of the way.
 
Take I-65 north to Elizabethtown, KY. You can choose the Bluegrass Pkwy to Lexington, and then up I-75 to Cincinnati. Or if traffic is lighter, stay on 65 up to Louisville, then take the 265 loop around to I-71 to Cincy.
 
From there it's through Columbus and around Cleveland. The first time we spent the night in Mentor, OH (east of Cleveland). The second time we went further and spent the night in Erie, PA. Here's where it starts to get really nice. I-90 takes you through the edge of PA and around Buffalo. The same road heads east through the center of NY state. The whole way is just beautiful. I forget the other name for this road - something like the "Cross State Turnpike" or whatever. When you get on east of Buffalo you go through a tollbooth. When you exit, you pay a toll based on how far you traveled. The price is reasonable. Every once in a while you'll pass a rest plaza with gas stations, food (Starbucks!), ice cream, etc.
 
Here's where you have to decide if you want to save time or see some beautiful country. If you don't have time to spare, take the 90 to Albany, and then head north up I-87 into the Adirondacks. Now how do you get over to VT? I highly recommend taking Hwy 74 east to Ticonderoga, NY, and then choose your route to get to Crown Point State Historic Park. There's a bridge there that crosses over to Chimney Point, VT. Oh my goodness ... be prepared with the "Shire" theme from the Lord of the Rings soundtrack. It will take your breath away.
 
If you have more scenic time, take I-81 north from Syracuse, NY, and then Route 11 northeast from Watertown. This road takes you through gorgeous places in extreme northern NY state. You'll end up at Rouses Point along Lake Champlain where you can cross a bridge into VT.
 
All in all, either route is something to experience.

A small one
 
hwy 25 off Hollister, CA .
 
more beautiful roads in california?
 
http://pashnit.com/motoroads.htm

Just about any road that's not the interstate works for me. And I've found that the folks in the little bitty towns way off the beaten path are often the best read and best informed about current events too.
  
@ tirthankar_b, glad to see they got the Old Priest Grade on the list.

My recent favorite road trip was from home in Plano, TX to the Talimena Scenic Drive on top of the Ouachita Mountains in Eastern Oklahoma and Western Arkansas. http://www.talimenascenicdrive.com/ US-75 north was boring as usual, but US-70 east had farms and fall color and US-271 added hills and forest. The main event is Oklahoma state highway 1, the Talimena Scenic Drive, with the following warning signs at the start.
 
"W A R N I N G"
"Narrow and Winding Roads Next Several Miles
Grades in Excess of 13%
Large Vehicles are Not Recommended"
 
Lots of turns and elevation change on Winding Stair Mountain with beautiful fall folliage when I drove it in October. Then drove south on US-259, also scenic, and spent the night at Beavers Bend State Park. Easy weekend road trip from the Dallas area.

"The Blue Ridge Parkway and Skyline Drive in the fall."
 
I drove part of this on Tuesday while on business in Asheville NC. Absolutely beautiful part of the country. Strongly recommend.

Highway 12 in Utah, Going to the Sun Road in Montana and any twisty winding road.

NY route 97 from Port Jervis to Hancock, much of it alongside the Delaware River.

Halifax, PA to Anchorage, AK...highly recommended! This is the route we took in JANUARY 2006 (HTML used do to link length): Google Maps Rules!
I don't have the patience to type out the details, but it was awesome, and we have so many stories from the trip. Maybe someday I can write out an Edmunds publishable grade post trip trip log? (Probably not after that sentence.) We also achieved Edmunds worthy fuel economy in our overloaded XL-7 with a best of 18 and a worst of 13 mpg!*
 
So many stories are running through my head right now, here's a little piece of one you car folks will appreciate. Temps of about -50 F can cause throttles to freeze in a semi open position, which is not a confidence inspiring situation when you are in 2-H, on a snow/ice covered road, in the Yukon, at night...the wee hours of the night. It was on that day that i stopped busting on GM for running coolant lines through throttle bodies.
 
More recently, I traveled to Boston (Somerville) for the weekend to visit my old roommate, his wife, and Cracker the cat. For some reason people find it funny that we named a black cat Cracker, I wouldn't know why. I found 84 to be scenic for an East Coast Interstate, in PA and NY, and I found it to also be an average speed in Connecticut at around 8:00 on a Friday night.
 
In Massachusetts I experienced to virtues of roundabouts first hand, and transitioned from a frightened out-of-towner to a novice in negotiating them. I have since been pondering up locations locally that they would serve better than the existing intersections.
 
Wikipedia claims: "Roundabouts are safer than both traffic circles and traditional intersections—having 40% fewer vehicle collisions, 80% fewer injuries and 90% fewer serious injuries and fatalities (according to a study of a sampling of roundabouts in the United States, compared with the intersections they replaced)."
 
"In addition to improved vehicle and pedestrian safety, and in spite of lower speeds, roundabouts dramatically outperform traffic circles in terms of vehicle throughput and, because a roundabout's circular traffic is always moving, they outperform ordinary junctions with traffic signals as well."
 
*Fuel economy not recorded in Canada due to lack of interest in doing conversions and not recorded in Alaska do to insomnia causing lack of interest in everything.

my favorite drive is from home to ny to skis in the winter.the boring flatland susurbs will look quite invitihg come the end of the week.no snowat home, but 6' is on theway. driving east the sun and snow glare are quite intense. snow(lakeffect), starts to fall i n the usually snow prone areas. whiteout to sunshine back to whiteout. through all this my06 impala ltz rides the snow perfectly.never at a loss for traction i feel confident in running at or around the speed limit. the impala is avery good all weather vehicle. get rid of the oem goodyears and we could really have something here