i find mw2 is just for fun and messing around
i find that cod 4 is just the best basic cod game with no bs(except for the hacks)
black ops for seriousness in a party pub stomping
Cod 4 I use to kick ass at that and managed to get to #6000 on the kills board and just over 10k on the Score board legitimately and my best moment was partying up with tnj08 (Old #1 on the score board) and having #70 on the score board on my friends list.
*Sigh* those were the good ol' days when cod was still acceptable to play. Now I just play Black Ops which I'm pretty good at and Have a 2.4kdr but I think the maps are shit and the whole online experience is pretty bad, but at least it's not MW3 bad, it's close though.
I've never played MW2 online for more than 10 minutes and I don't own MW3