I wasn't going to vote because I've never seen No Country for Old Men, but you guys have convinced me that Biff was pretty evil. My memory was that he was just dorky/bully.
I love that book, movie, and performance (NCfOM), but to me Biff is just more of a villain than a professional hitman trying to avoid the law. Especially in the sequel where he's basically infected the entire planet with his brand of scum. I went with Biff haha.
Same on Silence of the Lambs. Top ten movie for me, love the character, love the performance...but the whole reason Lecter is cool is that he really doesn't even want to kill Clarice and even tells her the world is more interesting with her.
Gary Oldman as Dracula would be the third performance I'd put in with those other two as just mind blowing amazing and complex, but I get why they said no horror characters. That one I might just say "best acting I've seen ever".