Yep, I definitely agree that we are in "greater fool" territory when it comes to housing in many US cities (i.e. "yeah I'm probably overpaying, but as long as someone is willing to buy it from me at a higher price who cares" or "yeah the real estate is double what is was in 2009, but I can make the monthly payments so who cares.")
With that said, I think some areas real estate is wildly overvalued, while other areas are fairly valued.
My extended family just bought a nice 4 bedroom house for $200K in Raleigh, NC. The economy is growing at a fast clip there, the state's budget is balanced, taxes are reasonable, and there are a lot of job opportunities. I don't think they will get burned badly in a real estate downturn. Similar things can be said for some markets in Florida; with businesses moving down there at a fast clip due to no state income taxes and lack of unions.
Contrast this with places like Northern New Jersey, with out of control taxes, budget deficits, expensive real estate, and companies realizing that they no longer need to be right on the periphery of NYC due to technology, and in my opinion there is a big dislocation in terms of value. I feel sorry for people buying at today's prices in NJ, CA, CT, Boston, Chicago, etc.