As Kabob noticed (by kicking my ass all over the map today), I finally started playing multiplayer. I'm one of those people that have to finish the single-player at least once before I can start playing multi. First thing I noticed last night, annoying high-pitched 12 year old are out in force. More interestingly, seems to be quite a few girls playing. Of course, this just meant the guys playing trying to hook up with the girls.
I was so sick I was knocked out all of Wednesday and most of Thursday. This threw off my sleeping schedule and I was up until almost 3 AM this morning playing. Woke up and then played some more. All the unlocks and achievements make this so freaking addictive.
I'm working through the Barret .50 cal sniper unlocks right now. I don't think I'll ever finish the FMJ unlock.