Go here:
http://www.stormingthetower.com/2010/07/13-webcomic-supervillains-poised-to.html
Vote!
(Although I do have to agree that they really, really missed the villainy in Girl Genius when they did this poll... but since that's more steampunk than superheroes I can live with it.)
As a bonus, there are links to webcomics I'm not familiar with. Enjoy!