While almost every speaker at the event lauded the strong fundamentals of the Washington, DC area's real estate markets and projected a strong 2007, Bernard Haddigan, managing director of Marcus & Millichap, noted that there are signs of weakness is some class B and C assets in a few submarkets.

"The best asset classes have cap rates that are lower than what they were a few years ago," he said. In some cases secondary assets, though, have seen cap rates rise several basis points. Marcus & Millichap, he said, is marketing some of these properties that have gone into foreclosure. "On the low end of the market the signs of [trouble] are there."

Most of the concerns expressed were couched in terms of slowing growth. Patrick Marr, EVP of CB Richard Ellis, does not believe a rent increase will reach 20%. "There is already a difference in the asking rates and actual rents received."