Open Coffee
Open Coffee was originally started in London, but Nicholas Butterworth, a friend of the original founder, started a group here in New York. It was a little slow gaining a foothold, but since a VC blogged about it it's exploded: mostly attracting folks looking for startup funding and seeking to "take it to the next level."
I go because the networking and discussion is great, and I think it's good to keep an eye on what the New York tech community is up to. What technologies are gaining in popularity? (Rails certainly appears to be on the upswing.) What new ideas are hitting the streets? How does a company go from a solo-start-up to an online phenomenon? There are a lot of interesting people at these meetups.
It does look like the venue is starting to get a little full. The format originally was meet and greet for a while, followed by introductions, and then coherent discussion. It's since devolved into multiple discussions at once, basically a free-for-all. I actually think that's a good thing since, to me, it's the networking that I come for, not necessarily discussing the macro-economy with fifteen other people. However, I'm sure Nick is looking to introduce some more structure and possibly a different venue.
I've seen a few other software developers (both solo guys and company fronts) at the meetings, and it's been interesting to see what sort of angle they take on things as well.