I hate to take the glow off of the Extreme Makeover's good feeling, however, there is another side to the story. Specifically, the case of the ex-Marine, here's what happens: they fly the family out to California for a vacation, and they bulldoze their house, and then in about a week, they build a new house, worth, let's say, $250,000. The family comes home, they take the blindfolds off, and here's the new house.
The part that isn't so good, is that the winnings from this show, namely, the vacation to California, and the new house, are taxable as regular income. The show issues a 1099 for the quarter of a million dollar plus figure, but tells the people that it's just a short term lease of less than 90 days, of which the improvements MIGHT not be taxable. The Internal Revenue Service, however, has ruled otherwise, indicating that the proceeds from the show are no different that winning Jeopardy or the Price is Right. By virtue of the fact that their family was chosen to be featured, they won the new house. In the case mentioned, there was a fundraiser to help pay the tax liability, which was over $100,000. If the money hadn't been raised, the IRS would have seized the assets of the family, as they had no regular income. Likewise, in some cases the families have had difficulty, because of their particular circumstances, in paying the increased property taxes and utilities on the new super-houses.
It's a nice warm and fuzzy idea, but what happens after the camera trucks pull out isn't quite as pleasant.