Sephiroth!!!!!!
i knew a lot would say it, too.
I had it pop in my head before I could even click the link.
I am dissapointed with lots of games due to lack of truly evil or fanatical bossess over the last few years. I feel one of the few flaws of FFX was the bad guy. i just wanted to say 'look, let's go KILL the bitch and get it over with'. noooooo we chase him for like twenty hours and it is worth it because the rest of the story ruled.... but as a badguy? Nah.
Kefka.
The dude in black from Xenogears ! (don't wanna spoil it for anyone)
that dark knight from FFT. that guy UGH! heh i hated that motherfucker.
Akuma!
Kain from Legacy of Kain. man alive that guy was evil.
the ex paladin from WC3. Revolver Ocelot is an altime favorite. your brother in Baldur's Gate & BG2 & BG:ToB. i forget his name, but he was cool.
i'm really, really tired of Ganon... dude.. learn magic that doesn't hurt yourself, okay?
I may post more later.