Try to find out what homes like yours, in your area are actually selling for right now. Comparable sales within the last month, if possible. Then decide if that number is ok with you or not. I would keep in mind that the last down cycle went from 1990 to 1996. If you think that this down cycle started in 2006, then there’s a good chance it will not stabilize until 2012 or later.
This is a difficult position to be in right now. I sold my personal residence in the early 1990’s and bought back in 1998. Saved me about 20% on price. And time on the therapist couch. As having a mortgage during that time was very stressful. Not so much from declining values, but from unemployment concerns.