I'm actually in the middle of making a soup for a potluck for my oldest child's class this evening at school, so my review will have to be quick.
We start to see Aang mastering controlling himself in the Avatar state, until he has to let go of Katara, but doesn't want to. Poor Aang! And when he sees Katara is in trouble, he's willing to sacrifice being able to enter the Avatar state ever again to rescue her. Although near the end, we see him enter the Avatar state during the climactic battle, but Azula shoots him down while in the Avatar state. There's been a lot of debate as to whether Aang was "killed" in the Avatar state before Katara healed him with the special healing water from the Northern Water Tribe. It will be interesting to see how that ends up playing out.
Oh, I swear I wanted to yell at the television when Zuko betrayed Iroh to help Azula. OK, I know Zuko was disappointed and jealous when, just as Katara was going to try to heal his scar, Aang and Iroh come in and Katara rushes over to Aang... but... but.. .Zuko!!!!! And I have a pretty good feeling that next season, Azula is going to double-cross Zuko somehow.
Speaking of Azula... damn, she's crafty! I loved how she turned the Dai Li against Long Feng, and her comment to Long Feng was priceless: "You weren't even a player." Long Feng definitely had that coming, although I hate that it's at the expense of Ba Sing Se and the Earth Kingdom.
Toph can bend metal! She *IS* the greatest earth bender in the world! :) Go, Toph!
I felt kind of sorry of Sokka, though... just as he "proved" himself to be a man to his father and was about to go out on a mission with him, Aang had to take him away to rescue Katara. I wonder how the water tribe's mission will play out in Book 3?
And I have to wonder is Mako (the voice actor of Iroh)'s death may have affected the ending. The last we see of him is telling Katara to take Aang and get out, that he'll hold off Azula and Zuko. Then, Iroh is captured. I suspect that Iroh was supposed to be Aang's Firebending teacher, but Mako's death may have forced this change. Again, it will be interesting to see how this plays out in Book 3.
In some respects, these last two episodes of Book 2 can be compared to The Empire Strikes Back. Book 3 will show Aang and his friends in their darkest hour, and hopefully we'll see a "good" resolution.
BTW, what do you think will happen to the Earth King as his bear? The Earth King is definitely a wimp, so it's not like he'll able to help Aang and the others all that much.
Speaking of the bear, I loved it when Azula's cohort won't fight the gang, and tells them to :"Just take the bear." :)
Sorry this isn't more comprehensive, but still have a lot to get accomplished today...