Songs that relate to bikes, cars, speed...
Red Barchetta by Rush
Trampled Underfoot by Led Zep
As the Rush Comes by Motorcycle
While I'm riding, I listen to everything from Led Zep & Rush to Delerium, to Crystal Method, to Depeche Mode, to BT, Massive Attack, to NIN...and more. I have a pretty wide range.
Hard Rock (esp classic) and Techno is the best for spirited street riding and track days. Down tempo & trip-hop is cool for laid back rides.