well i'm a fan of the gran turismo and is one of the main reasons why Im getting a ps3 (GT 5)
does xbox 360 have any notable racing game?

DiRT (click for more info) is supposed to be just as good or better than PGR3 and it's off-road racing! You should pick that game up if your into Racing games.
PGR3 and the new Need for Speed are also two really good racing games.