Under normal condidtions, mostly garage rock. Top picks are Paul Revere and the Raiders, Chocolate Watchband, and the Electric Prunes. There is also Redd Kross.
(No, I did not grow up with these band. I just found them. Well, I did grow up in the Redd Kross era.)
In the Viper, metal is a must. Basically, anything with grit. Joan Jett, GnR, Crew.
When just cruising the stars, pop rock is good, but never anything too wussy!