Clearly the greatest RTS game (and maybe even PC game) of all-time.
Everything's just perfect about it; great story, great voice-acting, great gameplay, great graphics, great music/sounds, great cinematics, great multiplayer and great re-playability (I've been playing it since it first ever came out)... It has absolutely no flaws and is a definite must have for every PC gamer!
The story and voice acting is the best part of it. You get this creepy chill up your spine from the very first cinematic and instantly fall in love with it from the first look of the gameplay. I cannot describe how awesome it is: you'll have to play it to see what I'm talking about.
Gameplay is fantastic! It is much more realistic than traditional RTS games (It doesn't have resource building, which is kinda lame in games) and its much more fun and action packed. The moment you're on the battlefield, the action starts and you're in the middle of a firefight. Almost everything in World in Conflict is new and innovative; the tactical aid points used for cluster-bomb airstrikes, tank busters, napalm, artillery barrages etc., lightning fast gameplay with no resource building or any other waiting thing, precise unit animations, completely fresh multiplayer and gorgeous gameplay interface to name a few.
Multiplayer is very addictive and very fast unlike other games of its genre which makes it really fun. The modes of multiplayer play is brand new and like everything else in the game, it is awesome! The only problem with multiplayer is that there are very few people playing it at a time but that's quite alright.
If you've never played it, GET IT NOW! Its one of the things you should do before you die: experience the world's best RTS ever made; World in Conflict.