I hated the combat shotgun when I first started using it, but now I actually like it. .44 is ok, should have stayed 2 slots. M4, not really sure about. It is a pretty common weapon worldwide. Also, MW2 is actually a decent game once you turn off that loud annoying music, at least the singleplayer is.
For the commando, I find the AK fine at all ranges. It is pretty much my "everything" rifle.