FORZA 3 4 and 5, ANY NEEDFORSPEED esp. ProStreet and Carbon....and The Crew (NEW GAME THIS YEAR FOR PC GO LOOK IT UP!!)
1 - Gran Turismo 1/2/3/4/5/6 2 - Rollcage Stage 2 3 - Demolition Racer 4 - Wipeout games 5 - Dirt 2 & 3 6 - Race Driver GRID 1 & 2 7 - Road Trip Adventure 8 - Colin McRae Rally 9 - F1 2010/11/12/13 10 - WRC 2/3/4 Honorable mention for Mario Kart Double Dash.
I've been with Grand Turismo since the beginning. I haven't gotten to play 5 or 6 yet though which are the best ones...