I can't believe nobody has mentioned the greatest in-game music of all time, the Interstate '76 soundtrack! I coped that sucker to eight-track and rode it around town in my muscle car for months after I got that game. In fact, the music has probably had more impact on me than the game itself. Fantastic.
They even released a soundtrack CD, which included snippets of the jive-talkin' dialogue as all the trendy movie soundtracks do these days. Check it out:
http://altpop.com/stc/reviews/i76.htm
A lot of the tracks can be found at various reputable networks by searching under Bullmark. Classic, classic stuff.