Are we at Bueno Nacho yet?

Just about any incarnation of Starscream from the many Transformers series. (The Prime iteration is by far the most amusing and tolerable, IMO.)

Original and bestest.

"He lived his life a warrior, and died a hero." RIP Dinobot.

Prince Zuko is an interesting case. The first time he's on the verge of teaming up with Katara, he betrays her. This is after having a supposed revelation about being happy in his new life. It takes a little more character development before he teams up with the Avatar for good, and it takes a while before anybody…

And he's one of the funniest.

As anti-heroes go, he's one of the most enjoyable.

Also, him.

Gotta love Deadpool. Of course, he more often comes through for his comrades than not, to the surprise of everyone involved. (Edit: Replaced picture with one of my favorites from the Dark Reign run.)

The one and only.