Yes, I'm a geek (or a nerd, or whatever you want to classify me as).
Why I am I a geek? Well, let's look at the stereotypes and see how many I fit...
I am intelligent (IQ roughly 140-145 range...borderline genius).
I like computers (and know how to work on them too).
I like science fiction (but have never dressed up like a Star Wars or Star Trek character).
I could care less about the current styles or fashion trends (I dress how I like, not how someone says I should).
My favorite game is Magic:The Gathering (lets me be creative).
I like old 70's "progressive" rock (hip hop/rap, with their repetitive beat, bores me).
I've worn long sideburns since 1975 (yes, I know Elvis is dead).
Know how to play chess (but don't play it well at all).
Was never "popular" with women (except as their "safe" friend)
On the other hand:
I'm married and have kids (so yes, I've kissed a girl, had sex, and don't live in my parents basement)
Love sports (was never very athletic, but still loved to play)
So that probably scores me about 80% geek. But frankly, most people that are classified as geeks are simply people who are self-confident and don't believe they have to follow the crowd. They march to their own beat, even if it's a different one than the majority.