I'm going to DC for a couple of days to see/hear Barack Obama's inaugural speech. While there, I will need to eat. I'll be primarily around memorials and things -- your basic tourist stuff. Is there good, inexpensive food to be had? I like everything! Though for the cold, places with great soup or pho or something, or big satisfying sandwiches, would be great.
I also wouldn't mind recommendations on less-well-known but still interesting tourist stops, since I'm sure that every place will be totally mobbed!