Here are some points missing from my original post.
The equity estimate is based on most recent comps. In the past 2 months, three houses with exactly the same floorplan were sold for $550K, $555K and $567K (larger backyard). MLS shows 1 house pending (asking price $575K). Based on these comps, our home seems to be worth $550K (I am taking lowest of these comps although we have put in some upgrades).
Prices in my neighborhood have come down by 10% from the peak (summer 2005). I’ve considered 8% of selling price as costs (6% for agents, 1% closing costs, 1% for misc).
We have a 30yr fixed loan, so the $2K monthly cost is pretty much guaranteed for next 30 yrs if we stay put in current house (exceptions: small increments in PTax, Ins & HOA).
If we don’t sell now, our concern is we might loose a big opportunity to cash out and invest it somewhere else rather than loosing equity.