Darth Vader, hands down.
sephy is to emo for me, an since his only claim to any actual fame is killing, Aeris -.- , he kinda fails, since he's not the frist bad guy to kill a good guy ( ExDeath in FFV kills Gualf, and i hear party members die in Phantasy Star 2 an 4) plus, every body tossing each other off over him is beyond old.
as for pryamind head, never played a silent hill game, so i've no coment there.
as for why i chose Vader, if you seen Star Wars ( the oridginal 3 not the newer ones) then you already know why :3