I had a great day on XBL today as well. Not quite to the levels of the Krookster, mind you. My best rounds were 26-3-6 and 20-0-4. I leveled up five or six times, and also completed / unlocked all of my challenges / attachments for the SCAR-H. Except for the headshots. I'm running a silenced Scar with the extended mags. Bling Pro, Cold Blooded and Ninja Pro for me. I still alternate with the Scavenger perk sometimes, extra semtex / frags and claymores never hurt.
And I really, really despise the Sub Base level. Wasteland also blows monkey balls.
Over four million people have played multiplayer. Crazy.