On the subject of 'Evil', I must confess I would prefer to avoid the label entirely when I think about my own villains. It is a bit like 'Insane' - a catch-all word too often used to mean that the author has given no thought to motivation or characterisation. It is fine for the heroes to label a villain 'Evil' or for the reader to decide for themselves that that is the case, but for an author it can be a dangerous mistake.
Labelling one's own villain as 'Evil' means it becomes easy to justify his or her every action on the grounds that s/he is 'Evil' and so lose sight of who s/he is supposed to be as a character.
Without motivation, villains merely perform vile acts seemingly at random, and so become far less scary than they should be.
At heart, a villain is no less a person than a hero is, and should be just as complex. Indeed, in some of the best novels I have ever read the antagonist is not 'Evil' at all - his goals merely lead him into conflict with the protagonist because of ideological differences, or because of the differing needs of their two peoples.
Just as a hero need not be without flaw, so a villain need not be without virtue <img src="/ubbthreads/images/graemlins/smile.gif" alt="" />
