So home buyers look like they're going to get a credit for 10% of the value of a home purchase, or $15,000 - whichever is less.

If we believe that housing bubble existed (or still exists), then shouldn't we let prices get back to market clearing prices?  Shouldn't we let prices adjust so that the "excess air" in the bubble doesn't exist anymore?  I'm afraid that artificially propping up residential real estate prices will just prolong this process.  Further, is housing really where we want to spend our capital?  Part of the problem with this downturn is that too much of our capital was spent on housing assets - I think it'd be healthy for our economy to shift out of housing into other asset classes - back to a more healthy equilibrium of some sort.  Lastly, while most people seem to think that home ownership is always a good thing - it should be noted that it does have some negative effects.  It actually decreases the mobility of labor, because people are more reluctant to move once they've purchased a home.  In this kind of labor market, we should actually be trying to increase the mobility our labor force.