Along with everything that's been said (except for Scavenger), I also really hate the match-making. Probably just as much as Commando....no, that's a bit far.
Yesterday, I joined an Search and Destroy match, got Commando-ed from around a corner so rage quit. I then pressed on Search and Destroy and joined the same lobby, half way through the round. So I quit, and tried again...guess what? Joined the same bloody lobby. Of the thousands of games being played, I joined the same one 2 times in a row.
I hope the match making is a lot better in Black Ops.