There's just one more thing- think about it a bit- evil is inherently unloveable. A sympathetic villain is not composed of pure evil; they are usually composed partly of good, partly of evil, and mostly of ego or anger (be it jealousy, disappointment, frustration, etc.). I think it's the combination of good and evil that people love, but not the bad parts themselves. That's also what divides stories from real life- you don't like assholes in real life, because they're just assholes. If you like them, then chances are that they are only assholes some of the time, and charming the rest of it.
And I don't want to hear about your characters at this time. I want to see them in print! (In other words- get writing!)
I'm not too fond of the good/evil balancing thing either, where good and bad are only such because of the labels stuck on them by the author. They are inherently
different, and should be treated as such. That's where Tolkien's imitators have screwed up; by failing to give different traits to their "good" sides, and their "bad" sides. Good doesn't need evil to exist, but evil needs good to exist. The rest of it's just bad writing.