It's weird: I usually don't play multipalyer games at all and I am by no means the greatest gamer, but whenever I do play multiplayer games my favorites tend to be stuff like tennis and fighting games.
I think it's just because they're simpler and more straightforward. I don't mess with weapon and gear upgrade systems and all that crap, I don't are about time-to-kill, squads or any of that crap. My favorite MP games tend to be ones with smaller player counts that take a more mental, considered approach. If I ever try another online shooter, it'll probably be CS, despite its notoriously high barrier of entry.