When I worked at a bookstore we came up with a test called the geek-o-lizer. The guy who scored highest was into video games, comics, science fiction and sports. The one who denied his geekdom the most was Dead Head. Somehow, following a band from gig to gig and recording their shows, then trading those recording for the ones you don't have doesn't make you a geek. To me being a geek means you're border line obsessed with something. Be it a TV show, a sports team or a band.
A nerd is just someone who excels at intellectual pursuits.