First off, I really dont understand the ‘throwing my money away renting’ mentality. Everyone needs a place to live, and everyone pays for it. If you are that unhappy renting, I submit you may be renting the wrong place. Owning a home is generally more expensive than renting on a month (compared to) month basis, so without appreciation or a 30year payoff, One could argue that owning is throwing your money away.
(I am mostly trying to show you that over the past 3 years, you have NOT been ‘throwing your money away’.)

As for worst case, that depends on the place you buy. How far is it from major employment centers, how old is it, how many other units are up a creek without a paddle? (How long will Americans allow our government to saddle future generations with debt they have little hope of ever REALLY paying back?) Some areas of SD have reset, others (I believe) are re-bubbleing, and some are still falling. Townhouses in Carmel valley are a different world than townhouses in Spring Valley.