"Opportunities of this magnitude come along once every 20 years or so," said Leisch, who presented Transwestern's outlook before some 1,000 people. Low prices and interest rates, the economist pointed out, will allow savvy investors to selectively accumulate assets. Prices in Washington will fall another 5% to 10% before hitting bottom at the end of this year or early 2011, according to Transwestern's Trendlines report. Cap rates in the area likely peaked in late 2009, and are expected to edge down for high-quality deals this year. Leisch stressed, "There will be opportunities to amass portfolios well below replacement cost."

Trying to time the exact bottom of the real estate cycle, he said, is a waste of time. Values, which have declines roughly 45% from peak 2007 levels, are low enough for investors to pounce in the Washington area now, said the report. Historically, Leisch noted, the sunset of previous downturns produced a couple of years of choice acquisition opportunities. "I believe we are in that 36-month window, where you'll have a few good years," he said.

Perhaps, but many of the investors in the room questioned just where these opportunities will come from. "Sure, it's an excellent time to buy, but the challenge is the lack of product coming to market in the area," said, Brian Connolly, senior vice president of acquisitions and leasing for Akridge. "People will not take assets to market until they have a clear picture of how to value it, but they need more data and there simply hasn't been much trading." Connelly related that there are a handful of deals in the Capitol area because sellers are not willing, or simple cannot afford, to dispose of their assets.