Excellent thread Erich!
Spielberg was asked how he made so many successful movies in a row and he gave credit to Hitchcock - when pressed further he said "it's really one of the best kept secrets in Hollywood" - hitchcock was surrounded by studio writers but when he selected scripts he always had one question "Tell me about the Villain" :)
Think of all your favorite movies (and blockbusters) and I assure you (with a few exceptions) I'll bet that film has an incredible villain:)
To that end my favorite villains are always ones I tend to empathize with on some level - versus the purely evil cookie cutter villains who's evil is unmotivated beyond that thes script requires a bad guy - tell us "how" he/she "became" evil is always a good place to start
Charlize Therons Witch comes to mind as this summers most amazing Villain - I also Think it's no mistake that my tepid reactin to Prometheus was that there was "no clear villain"
Good luck inventing your super villain!!