Points Bargain. Love the free internet... and breakfast would be a bonus.
Not one to make use of full service facilities.
Yes, we are planning to stay in DC itself for the first five nights.... we will be in Pentagon at the conference hotel for the final four nights.
Do you want a full service hotel or a points bargain?
Pentagon City is a bit out of the way from most of the things to do in DC, so you probably don't want to stay there for the vacation part of your trip.
For proximity to things, the JW on Pennsylvania Ave is hard to beat. Near the WH, walking distance to many Smithsonian museums, near the Metro. But it's a fairly soul-less, modern property.
Another good choice is the Mayflower. Good access to Metro, walking distance to WH, DuPont Circle.