Blizzard will toss us a curveball and make the final boss in Diablo 3 something we would never even consider. It's going to be a buffed up Duriel that uses as many as three ranged-attack spells, plus multiple auras that stack. He'll even be equipped with a shield and sword, posing an even greater challenge for the melee classes.

i think its going to be a skeleton king

baaal

this

Tyrael, like Izual in d2

hehe, maybe it'll be Atma
she's so nice to you in D2 act 2 (she talks to the ENTIRE GAME to lower your costs), she must have an ulterior motive. Nobody's that nice, even if you did kill the guy who killed her... mother? father? family? dog?

gheed .. we all know why

I think there will be not final boss

Yes. That would make the game super awesome.
End scene: Run through the gate unchallenged! ... Such an awesome ending!!