My wife and I just sold our home. We received an offer the day it was on the market. We can't be sure, but in all likelihood it would still be on the market if it weren't for the tax credit.
But that doesn't make me a fan of the tax credit. Like everything the government does, there are unintended consequences. A good friend of mine got a job shortly after I did, and he didn't get a chance to put his home for sale in time for a buyer to take advantage of the tax credit. The housing market is now artificially depressed, because anyone who buys a house in the immediate aftermath of the tax credit would feel like a sucker. The market he faces is very different than the one we faced, and I don't like his chances.
One solution might be for the government to be permanently involved in providing incentives for housing. Except we tried that. It's called Fannie May and Freddie Mac, and they are partly responsible for the collapse.
Markets go up and down. The government needs to let the market bottom out so that we can see a real recovery.