Crysis is going to be multiplayer? I was under the impression that it was more of a single player focus, with limited multiplayer.
Crysis is actually going to have a big multiplayer mode that will support more than 30 players. It's supposed to have some sick customization, too. I played two demo versions of Crysis, but both were single player so I haven't had the pleasure yet.
As for other FPS multiplayer games, I'll second Battlefield 2 and Call of Duty 2. Two others I'll throw out:
F.E.A.R., though I'm not sure how many players it can support. Plus, the multiplayer combat version doesn't have the "fear" factor (pun intended) of the single player campaign with all the spooky moments.
Resistance: Fall of Man. I'm just saying, if you're into the console thing and all, RFoM is a good choice for multiplayer action. Up to 40 players at one time with no lag or glitches or interruptions is pretty awesome.