Yu Yevon vs. Ultimecia

[spirawase]

um.. Edea was married to Cid, not ulti

[Little Miss Scarlett]

Ultimecia because she was always surrounded by awesome music. Plus, I find it quite fun to speculate about her origins. The most likely theory is kind of sad.

[S-r-ex]

Ultimecia. Even though losing the aeons for the final battle was sad and all and the yevon-aeon music was AWESOME(!!!), Ultimecia's three forms + Griever and the The Extreme and the fact that the entire final battle sequence wouldn't require a maximum of 14 regular attacks when levelled up a little. And Ultimecia has a scheme, Yevon's just lost his mind entirely.

[Meowster]

Even though Yu-Yevon was a horrible final boss, he at least was around for some time and not some random plot device found in the last 5/6s of a game.

[Nardack]

Ultimecia.

And I'm not saying that because she has tits.

[Thula]

Although both of them are one the 'wtf last minute ultimate villian' list, I'd say Ultimecia. Partially because the Rinoa-Ultimecia theory, if true, is the only thing I like about Rinoa.
And because Yu Yevon is not even a character