I just completed Season 2. There's just so much wonderful about this season (and this show in general).
What I found the most impressive was Pierce and his story arc. As I've continuelly mentioned in this thread, I used to be a casual viewer, so to me who only watched an episode here and there Pierce's behavior seemed extremely assholeish, over the top even. But only after watching this season as a whole did I see that was kind of the point, as detailed in the finale Pierce's behavior (at least in his mind) was justified because he kept being excluded by the study group.
And speaking of the finale, I loved the it (both parts). In fact since it was the first time I'd seen both episodes I was on the edge of my seat. Despite the fact that it was just paintball and no one would get hurt, the way the episodes are constructed really made me care who survived and who got knocked out.
Also as I mentioned before, I love Vicki Jenkins, and Magnitute is good too, but more of a one note character (and yes, I completely understand that that is the point
One more shout out because it's on my mind, I loved the "Office" episode and Abed's commentary at the end how the documentary format can work well. It was parody done but without malicious intent, and I liked that.