In 2009, a historic townhouse on Manhattan's Upper East Side hit the market for $28 million but didn't sell. The listing recently got a price adjustment—to $35 million. In Miami Beach, Fla., a home once owned by Jennifer Lopez went on the market for $29 million in 2010, but the owner didn't get an offer he liked. So he took it off the market for a year, then relisted it. The current asking price: $40 million.