Back in June 2006, when the housing market peaked, the prospect of a five-year national housing bust seemed unimaginable to most people. And yet here we are, with the latest Standard & Poor’s Case-Shiller index showing that prices hit new bear-market lows, falling back to 2002 levels nationally and to 1990s levels in some battered regions. Despite all the gloom, however, there are growing indications that it is a good time to buy. Mortgage rates, which fell to 4.55% for the week ending June 2, according to Freddie Mac, are near 50-year lows. Homes have become more affordable than they have been in years: According to Moody’s Analytics, the ratio of home prices to income is now 20.9% lower than the 15-year average through 2010, and 12.5% lower than the 1989-2004 average. A historic glut of homes, meanwhile, has created a buyer’s market: There were about 15 million vacant homes in the U.S. last year, according to John Burns Real Estate Consulting Inc.—some 3.1 million more than normal.