LOTS OF SPOILERS IN THIS POST
Just beat the campaign. Wasn't bad, but wasn't as good as CoD 4. Story was really far-fetched this time around. Like someone said, CoD 4 was cool because it was somewhat grounded in realism.
Anyway, hated the bits in Brazil. Really confusing level layouts and the enemy respawning seemed unfair. The bits in the US were better, but I didn't really love those too. I got the impression that IW just really loved Fallout 3, and wanted to demolish American monuments a bit. "Second Sun" was amazing for the ambience alone though (although the space thing was a bit too far). The Ghost missions were great. Loved the one in the snowstorm, and the one on the oil rig. The stealth missions are the most fun in Modern Warfare games.
"No Russian" was meh.
Did anyone else get a bit pissed off that Soap was made into a roided out freak with a mohawk? I sorta imagined him as a regular dude, and seeing him portrayed like this sorta cheapened both this game and CoD 4.
By the way, this may be absolutely obvious, but Gaz was Ghost, right? Seemed like the same voice actor, and the name really isn't a particularly subtle nod to the end of CoD 4.