Some of the original Driver games are great.
I'd recommend some older games first:
- Burnout Paradise (Not a realistic driving game, but hell it is fun)
- Dungeon Defenders (Off Steam for $20 I think, good 3rd person Tower Defense game to play with friends)
- SWAT 4: SS (Old classic, teambased tactical shooter, true to the tactical and teambased part)
- BF:BC2 (I recommend this because I'm not going to use Origin, and BC2 still has some decent servers here and there)
- Portal 1 and 2 (Need a good game? Play these, Portal is free on Steam if I remember right)
- Deus Ex: Human Revolution (Good bit of fun IMO)
- CS: Source (Can't really go wrong to be honest)
- Team Fortress 2 (Free fun, why not?)
These are just some of the games I've played in the past.