I like Star Trek, it's a good show. It's one of few things I watch on TV (I don't watch a lot of TV). I enjoy Voyager the best, because they are exploring unknown space.
I really think it's kind of wrong to assume that "everyone" who likes Star Trek is a nerd. It's one of those stupid stereotyping things. I hate that. Unfortunately though there are some "nerdish" Star Trek fans out there, and they have given the show that kind of name. So if you don't like the show or haven't seen it, you instantly think "oh, that's nerdy". When really, it's not too much different to other sci-fi shows like Farscape, etc ... except that perhaps it uses more technical kind of jargon, and like Death said, it doesn't always resort to violence.
And I actually have been to one Star Trek convention. I'm not afraid to say that I have. I did really expect to see lots of people dressed up, but there was only one person dressed as a Klingon. The convention was okay, and I got to meet a couple of the actors and get autographs. Although I did feel somewhat left out, as everyone was talking about the series on video, and I had only watched it on TV. I am not a huge fan to buy the videos or DVDs. I don't even care if I miss episodes (which often happens).
Although, dressing up as characters isn't quite that bad, providing it's not done in some obessive way. In the anime community it's very accepted (possibly because of it's popularity in Japan). I actually will be cosplaying (which is the anime term for dressing up as a character) as Yuna from FFX next month at an anime convention in Melbourne. I'm making the costume myself, and it's working out well.
Abe Babe...