That's the main reason I loved GT3 so much. I don't even like racing games, but it almost felt like an RPG the way I was building up my cars and earning the different licenses. I'll probably pick up GT5 now that it's $20 since I haven't touched a racing game since I bought 3 back around 2003.
--
http://soundcloud.com/thundersheep/lunatic-asylum
http://soundcloud.com/thundersheep/summer-rain