You San Diegans will not tempt me. I am breathing. I am focusing on my breathing. There is nothing but my breathing. In. Out. In IHATEYOUALL Out.
There, all better.
Arethusa, my fiancee and I did the San-Francisco-to-Philly drive two years ago, when we moved out here. Honestly, and no offense to any of the good people from the Midwest, but really, I didn't see any reason to stop in Ohio/Iowa/Nebraska/etc, except sleep. Wyoming was beautiful, though. Really majestic. We just took the 80. That got us out here pretty quickly, and on the western end of the drive it's pretty nice--Reno and the mountains, out into the salt flats, through Salt Lake City, eventually into southern Wyoming. If you decided to reverse those directions, you could head south along the California coast once you hit San Francisco, and THAT would be beautiful. Hwy 1 all down the coast... so good.
BUT if you want to take a real road trip, you'll probably want to take a route that doesn't have you driving 100mph in a straight line for days to start with.