Book 3 had the best villains in the whole series.

[Dark Riku]

IMO Amon was the best villain overall.

 

[ByakuganUser]

They are pretty cool, but i still think that Amon is the best one.

 

[Delcan]

Definitely as compared to the past 2 books!

 

[skay5269]

In my opinion it's:

1. Zaheer
2. Azula
3. Amon
4. Ghazan
5. Ming-hua
6. P'Li
7. Ozai
8. Long Feng
9. Zhao

is ther anyone i missed?...