I can't be bothered with the PC gaming myself as it seems to require you to significantly upgrade your computer every 6 months or so.
Vice City for PS2 is probably the best game ever I think. Huge map, tons of vehicles (the army chopper is just unholy), racing, fist fighting, car jacking, stunts, the ability to run around murdering hundreds of people at random without being tied down to a rigid, structured game. You just play this game your own way and it never seems to stop being fun. The only thing it's missing is a way to buy, sell and swap vehicles and properties which would make the money more than just your score. Never have I seen another game that has so many dimensions.
Lately I've been playing Downhill Domination for PS2. It's a super fun downhill mountain biking game with insanely big maps with crazy drops and amazing speed. You can also assault the other racers a la Road Rash (remember that one?). You can pick your bike from a bunch of real ones as well as upgrade the parts as you collect cash.
I feel a little light headed... maybe you should drive...