There's a pretty cool quiz at http://www.thesuperheroquiz.com/ which tells you which superhero you most resemble. I turned out to be the Hulk (70% likeness). This puzzled me until I remembered answering "all the way YES" to "do you anger quickly/easily?".
After you take that quiz, there's a link to find out which supervillain you most resemble. Looks like I have an 86% correspondence to Dr. Doom: "Blessed with smarts and power but burdened by vanity." (That latter part might sting if it were less accurate.)