I don't think of it as an insult at all. It might still be for younger people (high school and younger) because being called anything other than normal or cool is an insult. But I think the older you get, the less of an insult it is.
I've finally been able to settle into my own skin for the first time in my life. In doing so, I've discovered my true personality: I'm a geek! I used to hide it, but I don't care anymore. All of my friends are geeky or nerdy about something. Everyone I know is a geek in some way. The term "geek" for me is just a combination of intense knowledge and passion about a subject.
^ Make of this what you will. I didn't make it.