A Zillow (Z) analysis expects U.S. homes to lose $681B or 5.1% of their value in 2011 vs. a $1.1T loss in 2010. While the pace of loss has and should continue to slow, Zillow does not see appreciation ahead for 2012. Of the 20 largest markets tracked, Atlanta is the worst performer, off 14.7%. The best: D.C., down just 1.9%. Washington is a company town and the company is going gangbusters.