If you're a fan of touring cars and the WTCC then you'll love RACE07. I just picked it up for £14.99 from Game and have been having a hoot online, you get the odd moron who uses your arse as a brake but the for main online racing is frantic and fun... I break in to a sweat!
Physics wise it's pretty good, they've got the front wheel drives down well (not easy to reproduce in a game). Still, as with most Simbin games, the sounds outside of the car (for replays and spectating) is a bit shallow and high pitched but that aside it's a good mix with the support classes thrown in.
Radicals, Caterhams, Formula cars and Mini's.
As with most racing games the damage model could be improved, I'd rather it more realistic which would force players to take more car of their cars!
I actually race a touring car in real life so I'm pretty keen on things looking and feeling right, for the most part Race07 as a game/sim works well.

.. although I'm still quicker in the real thing than I am in the game!