1. Washington-Arlington-Alexandria, D.C.-Va.-Md.-W.Va.Total population (2009): 5,476,241 Median sales price (Q4 2010): $331,100 Median sales price % change (Q4 '09-Q4 '10): 8.1% Sales volume (# units sold in 2010): 97,860 Sales volume % change (2009-10): -3.5% Unemployment rate (Dec. 2010): 5.7% Foreclosure activity rate (2010): 1 in 49 units Walk Score: 68 Washington, D.C., was one of only two markets to see year-over-year gains in the most recent Standard & Poor's/Case-Shiller home-price index report, which tracks 20 U.S. metro areas nationally. While 11 of the 20 markets tracked posted new index lows in December, home prices in Washington, D.C., rose 4.1 percent year-over-year. The area's median home price rose 8.1 percent fro...