Grand Theft Auto: Vice City
This is became an instant classic, it's an open vvorld enviroment to build an empire and mess around inbetvveen, this title has a good feel, and the PC version allovvs easy downloadable customization, as in: alot 0f bonus looks, cars and extra secrets to the game, extra cheat codes & more.
Assassin's Creed II
The game itself is fun, good graphics, great storyline, and all around entertaining.
If you like Grand Theft Auto, you will like this game.
Street Fighter IV
Incredible Multiplayer-Online modes, a fighting bliss.
Sid Meier's Civilization V
A fantastic addition to the Civ franchise.