My first experience going to meetings was in Vancouver, BC when I was a student. The Vancouver IGDA meetings were just plain awesome - at least when I was living there. The meetings would only happen every 2 or 3 months, but EVERYONE would come out. It seemed to be a priority for both industry and students alike. Even during crunch folks would come out, watch the lecture (or panel or whatever), then return back to work.
Then I lived in Seattle, and the atmosphere of the meetings was very different. In Seattle all of the meetings took place on the Digipen campus (at least they did while I was living there). The environment of the meetings kind of dictated the sort of atmosphere. There were usually around 30 people at each meeting - mostly students - and they usually felt extremely casual. There seemed to be a lot less of a focus on networking, and more attention on skill exchanges and general love of games.
Now (after a couple years of not going to meetings I'm sad to say) I've just been to a Baltimore chapter meeting. It was great! The folks there seemed to be interested in exchanging skills, talking about games, and just enjoying hanging out (although it is possible that I am projecting my own feelings outward). It was a decent sized group - I would guess probably about 100 people - and a good mix of students and industry. I had an excellent time -- many thanks to the folks at Firaxis for hosting it!
I have to say that it was really, really nice to be back among game developers in this kind of setting. As an indie developer, I visit various dev forums frequently and try to stay connected online... but the experience is just not the same. There is something unique and very special about talking to others face to face. We as developers are kind of immersed in the culture of communicating over the computer and there are some wonderful aspects of that- but there can also be something lost. Developing as an indie can get lonely. It is nice to be reminded that there are a ton of other folks who have similar interests.
In 2 weeks I plan on sitting in on the DC chapter IGDA meeting - I am hoping that will be a lot of fun also.