Vast single player and interesting multi-player make this a game to ask the fat man to put under your tree.
As for the multi-player, it too is awesome. It's a much needed reprieve from all the first-person shooters out these days. (Gears, Halo, COD) I mean come on they release a new warfare/halo every year, it's time for something to really spice things up and this is it. Although it never gets as action-packed as those other games it does get highly intense. Walking through a crowd knowing that there is someone in that crowd ready to plunge a knife/syringe/axe into you. I also like how the scoring works, the guy running around on the roofs (visible) who shoots 5 people won't get as many points as the guy down in the alley who kills one guy (incognito).
All together it's a barrel full of monkeys, and who doesn't love monkeys.