Well, here's a list of good free games if that's a decent starter.
1) FPS - planetside 2, hands down.
2) Path of Exile - basically diablo 3 in a diablo 2 skin but better+deeper
3) Star conflict - sort of free arcadey sci-fi spaceship type effort
Do a google for "free PC games" there's plenty around, you'll get to try some good free titles that'll set your bar going forward
For paid stuff:
Fallout games - about best in class FPS/RPG
X-com games - about best in class tactical/strategy
Terraria/minecraft for cheesy sandbox buildy type stuff (terraria is a bit more RPG, minecraft a bit more world building).
Homeworld makes for a good "novel" take on RTS
Starcraft 2 series for a more traditional RTS
Bioshock for another story driven FPS
Elder scrolls series (get lots of updates and mods for it and skyrim still looks awesome, morrowind in the skyrim engine if/when they get it finished will be amazing).
Can't comment on good driving games if that's your thing.