I'd guess it's 90% commies, liberals, leftists, "progressives", and anarchists, with a few confused libertarians sprinkled in.
That's pretty much it. There is no regular people there. This isn't drawing the middle class or even the working class. Some unions are providing some support, but this sort of protest is filled with the same old lefties spouting the same old gibberish. And yes, there are some Ron Paul types there too as they make sure everyone can see their signs. For me, that is just another reason to dislike Ron Paul and his supporters.
I will say this though. There is, I think, a certain anger in the country aimed generally at what people perceive are high rolling financial types (traders, hedge fund managers, bank CEO's) who seem to do well no matter how much they screw up. TARP and the various bailouts did feed into this. People don't really know how to direct their anger so often just think very generically of Wall Street. The left tries to divert this anger into anti-capitalist rage, and we now see Hussein trying to play the populist anti-fat cat class warrior.