I've taken to blaring Pavorotti's Wedding Songs as loudly as I can tolerate while driving around town with the top down. It really makes everyone around me think I'm rich and snooty.
Then when no one is around I crank up La Grange by ZZTop, my favorite song in the whole world. In fact, the day I bought the car I knew I had to crank up some tunes from my home town band with the top down.
Creed is also good, and I also like Nickelback, but the lyrics are often so offensive I can't listen to them although the music itself is excellent for downshifting through corners