You're forgetting about the AVATAR! I don't think I can put them in order, but my favorite characters would have to be Aang, Sokka, and Momo. Zuko got pretty cool towards the end. Bender wise, my favorite characters are Aang (for the airbending) Katara, and Azula's lightning/blue flames are pretty cool.
I bought a little notebook with a picture of Einstein on the front for notes/doodles/ideas. Not much of a journal, but it's perfect for jotting ideas and quotes and little tidbits of information down. The only problem is that I've been carrying it for about two weeks and I haven't cracked it open once. If you do buy one, just make sure to get into the habit of writing in it. Otherwise it's a waste of money. I need to do this too.
Curse you Rise Against! I was going to be the first comment! You and your fast rising posting!