How could I forget Corypheus. As for as villains who want to become god go, he's actually pretty fascinating because his motivation stems from his sincere and fervent belief that god makes life worth living. His god betraying and abandoning him and the absence of The Maker shattered him and now he wants to be a god so there is some purpose or design back in the world and it isn't just meaningless suffering.

But, well, this isn't touched on enough. He's mostly just an evil jerk who looks stupid and spends the second half of the game getting dunked on.