I cant tell you one favourite, beacause of that im gonna tell you my top 5 racing games (not in any order)
1. Dirt Rally, Its the best rally racing sim i have ever played and until i try dirt 4 its propably gonna stay that way.
2. NFS Underground (the first one), it was my first need for speed and i played the heck out of it, so many good memories.
3. WRC 03 it was the very first racing game and with that the first ever game i had, i got it with my ps2 as a birthday gift when i was 5yo and it was the game that made me fall in love with rallying.
4. Gran Turismo 4, the best ever granturismo imo, the game was just so interesting an there was so much to do.
5. Colin McRae rally 2005, this game was the first rally game i played with a racing wheel and i remember countless nights playing it with my dad. It was the game that i learned to rally, its just awesome.
The top 5 being done i had 2 more games i wwanted to fit there but they didnt quite make it, them being the 2005 most wanted and the hated nfs pro-street, both games i loved as a kid.