Right, I usually only play TDM, Domination, and Ground War. All core.
That's probably why I never find anyone using it, it was so tuned down from MW1 that it's not really worth using anymore. I only use the UMP now, although I'll probably use the others on my next prestige for the mastery.
Team Deathmatch(Express or not) for ranking up, and Domination, Sabotage and Search and Destroy. You know, the old gameplay of CoD4. Plus sometimes the hardcore ones(that's usually I can find P90 maniacs).