Well it depends. If you are willing to wait (I would) I wouldn't get Crysis 2 because it has a much smaller user base than Battlefield and Call of Duty. Games with small user bases tend to suffer as a result (laggier games, worse support, less dlc, game dies out quicker ect.).
I have been playing Call of Duty since Call of Duty 3 (06), so I would like to think I know a bit about Call of duty. Call of Duty's rights are owned by Activision. They have a history of being especially greedy (eg: not giving dedicated servers which is key for online fps game btw, over priced dlc).
They are Just as bad in the fact that they don't let their developers (people who actually make the game) experiment or change up the game very much because they are afraid that if they do people will not buy as many games so lees $ in their pocket (greedy I know). Also this minimizes the things developers have to do between each release (One Game comes out every year so they don't really have too much time to work on it) so they can whip out more games faster. As a result each game ends up being the same game in essence as it predecessor and just a way to re-skin the same game you bought last to another 60$ out of you.
So yeah I realize that's alot of word up there but basically you are not missing any thing special. If you don't buy it this year then there will always be next. Now lets move on to why I think Battlefield 3 is the best buy: I don't consider myself a Battlefield veteran by any means but I have played a few of their games.
The Battlefield series is much better imho. It has much better post launch support. It has dedicated servers on consoles, which is a big buy in if you play on XBox or PS3.
It is much more balanced and has much more varied gameplay (eg: vehicles which actually contribute to the game, actually usefull snipers, unique roles between different weapon types not to be mistaken with perks which is something else they have in addition). It will have a beta to get glitches/bugs out of the way for you before you even play the game which MW3 will most likely not. Also this is the normal Battlefield title not Bad Company or Medal of Honor but Battlefield.
They only release one of these games every so often and this name is the biggest part of DICE's franchise. SO this game is a really big deal and I think they will put a lot of work into it. One more thing is if you care about graphics (I don't) is that battlefield 3 will feature an updated frostbite engine which will put Battlefield 3's graphics as arguably the best on console.
I could go on and on about all of the advantages that Battlefield has but I think I've made my point. There is no doubt that this is the better game. If you want to get the game that everyone else is getting and will be basically the same as Black Ops then get MW3.
If you want the better game but might not be as crazed (who knows that could change) then I would go for Battlefield 3.
Battlefield 3, great graphics, immense sound, destructible environments (at a level way beyond crysis and mw3) and a great community of gamers that aren't idiots :).
I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.