What 527s are going to go after Obama? The vast majority have their sights set on McCain. Besides, though part of McCain-Feingold was overruled, it will still limit them some in that the election is within 60 days of the nomination.
We won't have nearly as many on our side as the RATs will have on theirs, but ours have typically been very effective with their limited funds (e.g. the Swifties).
The media is giving Obama a free pass. McCain is giving Obama a free pass. Our 527s will not.
I'm betting the attacks will be pretty devastating when they come. There is soooo much material out there to work with.