Pricing Houses to Sell
The single most important factor to consider when selling a house is the home price tag: how much your house is worth.
You don't want to overprice the house because you will lose the freshness of the home's appeal after the first two to three weeks of showings. After 21 days, demand and interest wane. On the other hand, don't worry about pricing it too low because homes priced below market value often will receive multiple offers, which will then drive up the price to market.
Pricing is all about supply and demand. It's part art and part science, and no two agents price property the same way.
Source: Elizabeth Weintraub, About.com