Driving music!

I'll be flying up to Maryland on Friday to visit with the kiddo for a week and then driving my car (I CAN HAS CAR) back. It's a fairly easy drive, but it's also long and boring, which means music will be key. I'm rather lame when it comes to discovering music, but I'd like to have a bit of variety this trip in addition to my usual CDs. So here's your chance to pimp your favorite driving music. Tell me about your favorite songs and/or playlists for long drives. Any genre welcome. :) I will do my best to get hold of everything suggested to put together for the drive so it'll almost be like you guys are with me the whole way. :D