Most unique video game villian.

[I)eadnerzhul]

Mehrunes Dagon sucks. He doesn't do ANYTHING to you. He fights with Martin, sure! Spawns some Oblivion Gates... but NOTHING MORE. He is no real challenge, considering you don't even fight him, only his Daedra and Dremora.

 

[DarkDenizen]

Walton Simons from Deus Ex. He wasn't a particularly unique concept, but most game villains aren't as well donel as him.