I find that bringing a friend's the best. I've gone on a lot of "road trips" with people on this board -- and we usually don't listen to music, but denigrate eachother and spew filth and bile. Well, that's usually me, but..
If you're flying solo, just put the iPod on shuffle and don't skip anything. Good way to hear songs that fell out of vogue with you/you haven't heard in a long time.
Drive safe!