Like seriously, tons of kick ass titles are being released (or are out already)
Call of Duty 4, beat it in two days seems short but definitely worth the purchase.
Crysis, don't really need to say anything more besides GoTY.
Hellgate London, I'm personally not a fan of this game but people at work are loving this.
F.E.A.R. Perseus Mandate, Kind of blown away due to the other big name games that came out but I'm sure it will be a goodie (already installed!)
I think Shadowrun comes out this month too, and so does the new Need For Speed: Pro Street which is supposed to "revive" the series and get away from the Fast and Furious shit.