Personally I believe it is zuko becouse of the redirecting lightning. Iroh may have taught it but he perfected it. Iroh never used it enough to be said that he mastered it but zuko was and he redirected a large amount from Azula with only a second to prepare and survived.

Azula, she has blue fire, and lightning.

Toph is the most powerful. She can earthbend better than anyone else on earth, and can even metalbend.

Katara

It's obviously Azula. Not only has she mastered Fire and Lightning bending, but she has skills in weaponry and acrobatics as showed in 'The Day of Black Sun Part 2: The Eclipse'. She beat Aang and Toph and Sokka with no bending at all! As for the re-directing lightning, I'm sure if Azula was taught it, she'd master it easily, as she dose with anything.

Azula is a Fire Bending Prodigy.

Toph!

toph...I mean come on...she metal bends...thats never been done before, she pretty much created a new type of bending, well I guess technically metal is earth but still pretty amazing.

and azula is not the best bender obviously...she was crazy, and she failed in the end so...

i can't choose between Aang, Azula, the bloodbender Or Mai. cuz Mai can take bending away, Azula can lightning bend, The old lady can water and bloodbend, and Aang can do 5 types of bending, Air, water, earth, fire and Energybend!

aang, obviously. although bloodbending is awesome.

I like Zuko because he mastered the ability to re-direct lightnng. Iroh only invented and Aang almost killed himself doing it.

well, Xierf, Iroh is the first person who redirect lightning in the series. in the begining of book 2, he catch Azula's hand then redirect the lightning to the cliff to save Zuko. i think he already master it.

and i totally agree with you that the best bender is Zuko.
he handle Azula well in the Last Agni Kai with Red Fire.
seems like he dont need Blue Fire or Lightning.
after the end of the series, i hope Zuko keep practicing his bending. i believe he could be as strong as Ozai one day.
because, beside his bending, he got a very good Kung Fu moves

Yes but you could see how it hurt him. He ran away. Zuko can do i in a second. Iroh still has some attachments that prevent it like the hate for his son's killer.

whoa2 .. i think i should rewatch the episode.

how did you know that?
i thought Iroh has already release all of his sadness of the death of Lu Ten when he start to travel together with Zuko.

I think the best bender would have to be Toph. I mean she is the best earth bender in the whole world! She's the one that invented metel bending. But then again Katara is pretty good too. She can bloodbend, she's a perfect waterbender (almost) ,and water is all around us! SHE CAN PULL WATER OUT OF THIN AIR! I decide . . . Toph, she is the bestbender from my point of view.