I'm surprised this dude wasn't mentioned yet:
Before we find out that he's a c00n, you can't help but feel and ask "This guy is a villain? What's he doing wrong?"
Let's look at past villains from Avatar:
Sozin uses a comet to gain power and instigate a 100 year war to spread Fire Nation supremacy, he wipes out a race in the process...
His successors carrying on his efforts to expand after he dies...
Ozai using the return of the infamous comet to barbecue every country not down with the Fire Nation... :welldamn:
Amon learns the power to take away bending and uses it to "even the playing field" for everyone, no bodies dropped...
It's shown that benders have the potential to be some real nasty bullies I can't help but root for nikkas like Amon looking out for the normal guys. I know if I was in that world and with no bending abilities, I'd roll with Amon's group asap. Especially if I've been extorted or beat on by benders.