I loved Crysis 1 and Crysis wars, but they are very different from Cod and most other shooters. A majority of the multiplayer gameplay is closer to that of Battlefield, but their is an element of advanced gameplay that resembles quake and other fast paced shooters. This advanced gameplay has a skill depth and learning curve about 10 to 15 times that of most other shooters, perhaps 20 times that of Cod games. It took me over 9 months playing 25 to 30 hours per week to get to my plateau, and another 6 months before I reached a peak. I think I plateaued at Cod 4 after 2 or 3 months...then got bored.
Crysis 2 is actually closer to Cod than crysis 1 and crysis wars as far as gameplay is concerned, although it is deeper than Cod as well. There are some things about c2 that are much improved in the gameplay over C1 and Wars, but if you are a Cod fan you will feel more comfortable with C2.
My preference is hands down Crysis 1 and Crysis wars over Crysis 2, but both of these games are on the verge of death at this point and you will not find many full servers like you will with most other shooters. Crysis 2 was fail by most PC gamer's standards and therefore appears to be on the brink of death as well. I don't know if I would spend 60 bucks on it (I didn't and I am, ?or was a hardcore Crysis fan).
However, you should be able to find Crysis 1 and Crysis warhead (comes with crysis wars) for relatively cheap (look for maximum edition). I would say it is worth trying out if you want a challenge. You can also download the amazing Mech warrior living legends mod for Crysis wars (which is spectacular for a mod imo)...which essentually gets you 2 singleplayer games and 2 distinct multiplayer games all for under 30 bucks last time I checked.
And yes I also concur with there...tf2 is free and lots of fun right now.