Yeah, everyone has different definitions they operate by. I consider myself a nerd first and foremost.
My personal distinction follows something like this:
Geeks have a particular expertise or knowledge of a single field, generally of a science or popular culture icon. Thus one can be a computer geek, a Star Trek geek, a Star Wars geek, etc.
Nerds are classified by a heightened general intellect and a lack of interpersonal skills.
Being one hardly disqualifies one from the other, and a single person could embody multiple geekdoms. So it falls to each person to choose which classification best suits them. I enjoy my pop culture, but I tend to be diverse in my tastes and lack the depth of knowledge shared by those truly devoted to a single fandom. But I am an engineer who suffers from nausea at the mere thought of public speaking. Thus, I am nerd, hear me roar.