Stayed at the Hay Adams for the 3rd time in mid December 2012 for a business event. Amazing location...right next to the White House. Great restaurant, rooms and service. Beautifully decorated lobby and common areas, and the basement bar is historic and memorable.
My only complaint is the creaky floors and neighborhood noise in the rooms. Tough to address in a historic building, and definitely NOT a reason to avoid, but worth noting.
Don't miss the 9th floor view of the White House!