No Counter Strike on this list? I wanna add it. All of them are awesome, though rough for beginners, but are the quintessential FPS. Graphics improve with versions, but some will contest other game elements are lost. CSS looks great, but it has the largest head "box". Personally, the monumental standout besides graphics of the versions is weapon recoil. Shoot an AK47 in CS and it's dead on, but subsequent shots are screen wide all over the place. Shoot an AK in CS:CZ and it isn't as dead on, but the group is a little tighter. Shoot an AK in CS:S and the first shot is dead on, and in spray mode, the 5th shot should be dead on again, due to the pattern. I like the shadows CS:S adds. One more thing to note, though all of these games feature the same maps initially, your character model size is drastically different. CS, you're big in the map, CS:CZ you're tiny compared to the map, and CS:S you're big again. Find one and have fun...or eventually rage quit.