Most of my favorites have been covered as well it seems, but here we go anyway. These aren't in any particular order by the way.
Scar (The Lion King) - Like many people said, best villain song ever. I also find him highly intriguing. What happened in his life to make him so bitter he killed his own brother? How did he get that Scar?
Zira (The Lion II: Simba's Pride) - She was a rather bad a lioness. Had a pretty cool villain song to.
Frollo (The Hunchback of Notre Dame) - Yet another awesome villain song. I didn't watch this movie much as a child, maybe once or twice, but I remember he scared the heck out of me. I really want to watch this movie again now, but I only have it on VHS and am no longer in possession of a VCR. I did buy the book a few months ago though so maybe I'll read that first.
Shere Khan (The Jungle Book) - In all honesty I don't think he's that much like Scar, something is different about him. Scar was all brain. Shere Khan was brain AND muscle. He was clever, charming and didn't need to really hide behind anyone to get things done.
Hades (Hercules) - He was just so hilarious, I probably shouldn't like him as much as I do.
Facilier (The Princess and the Frog) - He was really creepy and pretty evil, but somehow cool at the same time.
Lawrence (The Princess and The Frog) - Not really a villain, more of a minion. It's kind of just like how I am with Hades, I find him amusing.
Kronk (The Emperor's New Groove) - Another minion, but considering he was the villain's sidekick in the first movie in least I think I can add him here. He was hilarious and endearing at the same time.
And er...I know there are probably more, but this is all I can think of at the moment.
For I am convinced that neither death nor life, neither angels nor demons, neither the present nor the future, nor any powers, neither height nor depth, nor anything else in all creation, will be able to separate us from the love of God that is in Christ Jesus our Lord.
NIV, Romans 8:38-39.