SF also seems to be Mecca if you're gay, at least a certain kind of 20-35 year old gay man, too, which has a huge crossover with tech workers. I know it's been a great way to recruit at previous companies -- find the gay kid who is a developer or designer stuck in some crappy midwestern/southern town and help him relocate to San Francisco with a good job. But most of the older gay people I know later end up becoming boring and move to Walnut Creek or whatever to have a family, just like other people as they get older. Presumably NYC has the same thing going on.

I've only ever really been in the dating scene in the bay area for a month or two a couple times, and ended up with girlfriends rapidly. I guess being involved in the rave/party/etc. scene, and being interested in smart/confident/etc. vs. a lot of other things = easy mode for dating? But I don't really have anything to calibrate against other than MIT.