my online fix is really just BF4 at the moment, but I love it.
I also started playing DayZ about 6 weeks ago, the Arma2/Dayz mod not the standalone, and I really enjoyed that. I'm kinda waiting on the standalone getting to a point where it is really really good, at the moment it looks just meh. CS I've always thought to be really gash, never got into it, hate the feel of it. L4D as well I thought was totaly crud, can't stand how the zombies feel and the lack of a decent story. Not fussed on the whole drop 4 players into a world spread of 6 different chapters with no narrative.
So, I'm happy with BF4 at the moment, more than happy. I'll get The Division, and GTA 5 if it ever drops on PC, and then the big one is Star Citizen. But that's all I'm kinda interested multiplayer wise.