Right now for no-brainer shooters I'm tossing up Mag and MW2, but this got me interested as a real Army sim, where tactics actually have a role. Having not played the first one, I'm very interested. Having said that, Bots look real shifty to play with, but co-op looks like it will rock.
 
If I do get it, I'll get it for PC for the editor.

OFP2 makes the right changes to the sim formula that still make it really simulation driven, but fun to play for those of us who aren't completely in the hardcore simulation camp.  The presentation is better, the voice work is better(though still slightly hilarious at times), and I've never once questioned while playing whether or not it needed a few more months of serious development. Maybe about a week more of Q&A to fix some minor but obvious bugs, and that's about it. That question certainly came to mind more than once while I played Arma2.

Not being a hardcore simulation guy, I was never really interested in ArmA II except for the insane range of weapons and vehicles, but after looking at a few reviews, it seems to lack the polish of an actual game that OFP2 has. The bots still seem shifty, I saw footage of one walking right into the player's stream of fire, and they're one of the few complaints from reviews, but I'll definitely get this for the Co-Op.
 
Ugh, so many games, so little money.

Coop and competitive is awesome. Problem is the singleplayer is quite underwhelming, and you'll need to go through it to unlock all of the maps for use online. Bummer.