It's happened before, and it'll happen again. I've talked to coworkers who bought in the late 80's/early 90's when the market was doing this same thing. Crazy growth with no end in site. After it burst, alot of them were upside down on their townhouses/condos. Being upside down on a mortgage is not a good position to be in! It wasn't until the last couple of years that they recovered. And these guys are in the northern Virginia/DC metro and northern New Jersey/NY metro areas. Not exactly what you'd call economically depressed areas.
Right now it will go on, at least in this area, because there are jobs and there is a demand for housing. But it will reach a point where starting salaries will have to be way higher than what they are now to attract people to the area. As it is, young professionals making good money are stretching their budgets to the absolute maximum (50% of gross income spent on the house), just to get into the smallest houses available. Unless salaries increase by 20% a year, something has got to give.