I have posted this before on different threads, this is my opinion on the kiss.

This is what i think happened(facts in black orinions in blue) :

Both Aang and Katara stay after everyone else goes into the sub.

*they want to talk and are afraid of might happen.

They say the other's name at the same time.

*they just want to talk to each other directly (which should be easy because no one else is there except them and appa)

Katara gives her appreciation speech.

*She is telling him how he is growing and changing from a boy to a man, I think she is trying to say that he has grown up and changed, and that she admires him for that (not romantically). idk if she flirting or just very shy, she is hard to read(probably both )

When she leans into Aang when she says "I'm proud of you"

*She is acting shy, maybe a little flirty, but not the "i'm in love with you flirty"

When Aang says, "everything is going to be different now isn't it?" and Katara moves her hair.

*She was flirting a little bit but nothing major.

Aang says,"what if i don't come back?" and Katara replies,"don't say that of coarse you..."

*That was scary for both of them Aang brought up not coming back and Katara did what all friends would do and assured him he would, i can't find much romance for this particular part (not counting the kiss following).

Aang kisses Katara who is surprised by the kiss.

*Well wouldn't you be surprised if your guy-friend just kissed you? I know i would.

After two seconds (i counted, twice) Katara calms down and is not as surprised.

*she leans into the kiss and kisses him back, because she has started to like him "more than a friend" (imo) this season.

Katara still has her lips puckered even after the kiss.

*She liked the kiss and kissed him back, also the kiss just ended a second ago.

Katara looks down after the kiss with Aang.

*She is confused about what just happened, and afraid her friend might die, that was the last thing he said to her was "what if i don't come back."

She looks at him as he flies away and blushes, with a frown on her face.

*She is blushing because her guy-friend just kissed her, she is sad because (as i said) she doesn't know what will happen to him and herself. She also is in deep thought about the kiss.

(after the kiss scene) Katara is the first to notice Aang coming back on his glider, after he found the capital and palace empty, and she sat down when he sat down.

*She just happened to look in the sky and see Aang. The reason that she sat down when he sat down was because it is easier to listen to someone when your level with them.

When aang goes to take down the war balloons katara takes appa and goes with him.

*She did what she could to help just like she said.

Aang is on Appa crying and upset about the eclipse, Katara then goes over to him, touches his shoulder, and gives him a reassuring look. She also stands up with him.

*She goes to comfort her friend and assures him that everything going to be alright (yes i was thinking of the song no one here). this points out that there should be no awkwardness between them. Unless they decide to be boyfriend and girlfriend.

This whole essay is just facts followed by my opinion. I hope i didn't offend anyone, if i did i apologize.

I voted Zutara.

Because... they'd be hot together (HAHA! Pun intended! xD)

I enjoy sexy ships ^_^

Then there's the whole fire/water thing - it just WORKS, especially if you look at their specific bending elements in a metaphoric manner.

I'm not an avid shipper, but, I really much prefer them together. Ever since Zuko grew his hair out and that cave scene in 'Crossroads of Destiny' (not sure about the title) or something. Yeah.

Zutara FTW ^_^