I made it down in the drizzle to the great atheistic coming-out. I was surprised by the gender balance; a Washington Post article said at least half the attenders were women. Ethnically, it was overwhelmingly white, though black atheists were there and visible (there was a Black Atheist booth in the tent).
The highlights for me were: Tim Minchin, consistently funny and incisive. How he can cram a complex philosophical idea into two lines of poetry I don't know. And Nate Phelps, son of Westboro Baptist preacher and hate-mongerer Fred Phelps. To me, this was the emotional core of the meeting. Nate talked about his pain growing up in that environment, and the struggles he had breaking free of it, and his sadness to see his family there and the gulf between them.
Dawkins gave a good speech, as usual, but ended with a disturbing call for atheists to ridicule religion. Ridicule can certainly be an effective rhetorical technique, and I enjoy me some PZ as much as the next atheist. But ridicule is no part of rationalism. At a Reason Rally, we should have been talking about how to use reason more effectively, not how to circumvent it with cheap rhetorical tricks.
I live near DC but have been avoiding big rallies like this for many years: they seem to bring out the worst in people. This one was different. It had (for the most part) a very positive feel; a celebration of reason and science, and an opportunity to be surrounded by people who draw their wonder and joy from the real world.