Along with grand trismo....but their coming out with the #5 soon so i'd wait for that...but again im not sure if these will be PC only or both for mac and pc.
The Gran Turismo series has been and probably always will be a playstation only game.
As for mac/pc racing games, there is not much out their, depending on if you are looking for arcade type or realistic. Race '07 is pretty good, i played the demo of it on steam for a while, on a keyboard, and it was fun, hard, and realistic. It is probably much easier with a wheel. Of course you will have to boot into windows to play, so it depends on if that is an option for you or not.
I bought Rally Shift for OSX, I don't know if it had steering wheel support or not. But you could check with the guys at codeblender to see. It is a pretty short game, but at least somewhat realistic.
There is of course the NFS series for pc with the exception of Carbon for both pc and mac.
Redline is supposed to be pretty good, but i haven't given it much of a try. I played the demo for a bit, but it seemed kinda weird to me. But it wasn't too bad.
Racing games our my favorite games, and of the games i have spent the most time with they would probably be Gran Turismo 2, Gran Turismo 4, Gran Turismo 3, Need For Speed Underground, Gran Turismo, Need For Speed Underground 2, and then probably the original Need For Speed.
I hear GTR2 is an amazing game, but I have never tried it.
I think your best luck is to stick with consoles. The ps3 will later this year get Gran Turismo 5, which is gonna be crazy good, for those that can afford the whole set up. And of course the Xbox 360 has Forza which is pretty good.
Hope this helps somewhat, I will be watching this thread to see what other people suggest.
Enjoy
