Why do people even mention MW2 as one of the top FPS games? In terms of popularity, yes, it takes the cake. I am assuming they mean best when they say top, and MW2 should be no where near the top 100. I haven't played an extensive amount of Killzone 2, so I can't say. Halo 3 should be higher than MW imo, since it was a better game and took more skill (subjective). Bioshock was good, but a little overrated imo. I can't argue with orange box, great games into one package. Now I know...
I wouldn't say MW2 takes more thought and strategy, because that almost means more skill. Quake and UT take waaaaay more skill to play than MW2. I guess is that they would be different since COD is way slower, you don't have to process your strategies as fast as you would have for Quake or UT.
Because people like it because they feel they are good at something. COD is the most rewarding game ever made. You can completely suck at the game, yet the game still rewards you by giving you an overpowered deathstreak like Painkiller. If you're "good" at something, you're more likely to keep on playing it. COD is so unbalanced, the mass majority of people exploit this, and get a lot of kills (Shotguns, OMA etc.), giving them the false idea that they are good.
If you think COD MW2 if fast paced, you've obviously have never played Quake or UT
Is ninja really not on the list? It's the best perk in the game.