Quickly -- my takeaway of today's announcement:
As I've said before, I'm not sad about DOMA going away, but I think punting on Prop 8 was a very bad thing to do. Basically what it means is that the referendum and initiative system in California is a dead letter if (a) you can find the right federal judge and (b) the governor decides to abdicate the responsibility to defend duly enacted laws. That's going to bite California in the butt and it will have implications everywhere else. It's no damned good if government officials can simply ignore laws they don't like and get by with it. It's even worse if they use federal judges to backstop them.
Fearless prediction -- someone is already preparing a lawsuit to send to the 9th Circuit that would make Prop 13 unconstitutional. Have fun with that one, California.