Been reading some very good posts and articles about the term genius lately. First, this absolutely hilarious short story written by Isaac Asimov. It really brings home the point. There's so many different kinds of intelligence, but unfortunately the logic and mathematical intelligence seems to be the only one that counts.
A great blog I'm following is The Genius in All of Us, written by the author David Shenk. I recommend reading this post. He is debating the relation between being a genius and doing great deeds. David states that there is no such thing as an "unaccomplished genius". You have to do something that's truly ground breaking to be one.
The always interesting Scott Adams have recently written some good blog posts on this topic too. Especially these two questioning what intelligence is, and this post on people who believes they are special themselves. I totally agree on his arguments, especially the one that believing that you are something special "will blunt your conventional intelligence".
A person I consider a true genius is Richard Feynman. There are heaps of brilliant quotes from him and I recommend looking for the interviews with him that are available on Google Video. His curiosity is impressive. (Fun comic on Feynman and John Nash)