I wrote a Twitter thing about this earlier, but here's Ezra Klein's take:
Imagine telling a Democrat in the days after the 2004 election that the 2006 election would end Republican control of Congress, the 2008 election would return a Democrat to the White House, and by the 2010 election, Democrats would have passed a bill extending health-care coverage to 94 percent of Americans, securing trillions of dollars in subsidies for low-income Americans (the bill's $900 billion cost is calculated over 10 years, but the subsidies continue indefinitely into the future), and imposing a raft of new regulations on private insurers. It is, without doubt or competition, the single largest social policy advance since the Great Society.
I will always get a little barfy over losing the public option, but I think progressives and the netroots have much to be proud of -- and we still have a lot of work to do.