Whats the best first person shooter for the PC right now?

Both Crysis and COD4 looks really nice but I haven't had the chance to play either one since I need to upgrade my PC before dishing out $$ to any new games...I am still playing S.T.A.L.K.E.R. at the moment, it runs just fine on my system and still fun to play even after finishing the game once or twice...

if COD4 is as good on the PC as it is on the PS3, i would say its one of hte best out right now

if COD4 is as good on the PC as it is on the PS3, i would say its one of hte best out right now
My co-worker is also playing COD4 on his PC and he was quite impressed with it as well both single and multi player is really fun according to him so I may actually buy the game then upgrade my system later on...

just finished the single player of COD4, its fun but a bit short. Online and lan is hours of fun though. Crysis is fun, played it on a friends system and seems like it would be worth a go through. BTW they play fine on my laptop, Everex XT5000T, which my friend also has. Only upgrade is a second gig of ram for a total of 2 gigs. Which vista is more then happy to help eat up.