I came across a thread like this over on AutoGeekOnline.net and I figured I’d see what all you Oppo’s had to say on it. Some of my favorites:

Kickstart my Heart- Motley Crüe
Ride the Wind- Poison
(I can’t Get No) Satisfaction- The Rolling Stones
Nothin’ but a Good Time- Poison
Girls, Girls, Girls- Motley Crüe
Separate Ways(Worlds Apart)- Journey
Too Fast for Love- Motley Crüe
Welcome to the Jungle- Guns and Roses
Thunderstruck- AC/DC
Wild Side- Motley Crüe
Youth Gone Wild- Skid Row

For that late night, relaxing driving:
It Was a Good Day- Ice Cube
Nuthin’ but a G Thang- Dr. Dre
Gin and Juice- Snoop Dogg
Stairway to Heaven- Led Zepplin
Ignition(Remix)- R. Kelly
California Love- 2Pac

I’ve got some others that I like that are much more current, but I'll leave it at that for now.