Basically anything over about 3 years old should run alright. For first person shooters I would recommend System Shock 2, Deus Ex, Half Life 1 & 2, Far Cry 1, Max Payne 1 & 2, Prey, the older Call Of Duty and Medal of Honor games.
You can visit Gamespot.com for reviews and reference on previous and latest games. And youtube too, to see the actual gameplay for you to aprreciate the graphics. I used them both as reference before getting the game.