Mass Effect 2, because fighting a killer sentient space ship on foot is epic.
This as well, took me a little. bit to figure out what one to killdeth2munkies said:Lavos from Chrono Trigger.
Killed his face, figured he'd have a second form. Came inside, killed off his inner-form, thought I was done. Killed the center bit twice before I realized, HEY, that bit on the side is the actual boss ><