Modern warfare 2 for me.... I got Black ops and the campaign was allright, got really easy in Veteran after first few missions which was dissapointment really. But the biggest dissapointment for me is the fact that Sniping is ruined: Not just Quick scoping ( WHY THE F would you remove the 1 thing everyone loved playing in private matches a year after MW2 came out). But Hardcore scoping aswell because 1) the maps are so badly made that there is hardly any sniper spots and the few sniper spots there are, aren't good for surviving or has little traffic and 2) With no stopping power, unless you shoot them in the head, you get a hit mark - now i'm not the best sniper guy but i would expect to kill someone if i shoot them in the bloody chest with a Bolt action Sniper in 1 shot.
Perks in Black ops are stupid, the challanges to unlock the Pro versions of Perks are even stupid-er and the contracts are a very stupid excuse to add something new to the game - their either too easy and pointless or are forcing you to do the exact same thing just so you can complete it....
Zombies, yes fun, yes very hard for the casual players specially when your friends just don't get it that shooting zombies in the head gives them more points.
Killstreaks - Nuke in MW2 gave something to aim for but also contributed to a bit of camping, removal of nuke in BO and what? Even more Campers... Proves the point that Nukes were not the reason for Camping.
Guns: Yeah i like decorating my gun freely and my reticle, BO gets that but the guns itself are in my opinion unbalanced. Shotguns and Snipers are unused because they are way too weak - why include them at ALL?