Voldemort turned himself into pure cruel evil. He delighted in terrorizing others and he enjoyed torturing them.

He came in at #1 on the list ahead of Hannibal Lector of Slience of the Lambs, Lord Vader from Star Wars, and Cruella who wanted to make a coat out of the puppies. I guess we all agree that Tom Riddle turned himself into the #1 movie villain.

It was interesting to read that there was another from the HP cast who made the list but not in his HP role. Snape's Alan Rickman made the list of Villains for his portral of Hans Gruber in the first of the Die Hard movies.