First, I need to ask "Do you need to sell?" If the answer is yes, then go ahead and sell. If the answer is no, then I would ask you another question. "Are you downsizing or going for a bigger home?" If you are downsizing AND you don't need to sell, then you should wait. If you are looking for a larger home (or just more expensive), then you should go ahead and sell your home and move into the other.
Let me explain. Let's "assume" that home A was $150K several years ago and now it may "get" $135K out of it. That's a 10% "loss" of $15K. Now let's assume that home B was $300K at the same time of home A and now it may get (assuming the same 10% loss) $270K. That's a $30K "loss". If you were in home B wanting to go in home A, that would be a $15K "loss". And if you are in home A wanting home B, then you get a $15K "savings" getting into.
However, this is not really a look at reality. In reality, there are many areas which really didn't take such a hard hit in this recession, yet other areas may have. There is also one hard truth. The higher priced your home was several years ago, the harder the hit. I've seen homes get 50% "decreases" in value if they were in the millions.
Also, you need to look at the current situation. The wave of the initial rate adjustments is done, yet there is another big wave of adjustable rate mortgages which will reset between now and mid 2013 or so. So things may get worse. You need to think of being thrifty even if you must move unless you can ride through the next wave. If you are financially well off, then riding out the storm could be a good thing. I can't say for sure that things will get worse because I don't have a working crystal ball.
If you are moving down, then do so now. If you are moving up, then perhaps you should wait a few years for the larger home price to fall further (if they do). Yet with the rate where they are now, I do not believe that they will get any lower.
I hope that clarified things a bit. Or at the very least, give you more to think about.