Is the offer on your house still higher than what you paid for it? If it is then it's worth considering as you will pay a bit less for your next property but leaving you quids in when the market picks up again.
I personally wouldn't move house at the moment, but that's more to do with I'm happy where I am than the current state of the market.
If you can guarantee a profit on current property, despite it's lost value already, if you can guarantee that you will be happy to stay in your next property for at least the length of the crash, if you can guarantee that you will have an income for the duration to make your mortgage payments then why not?