Filter Coffee House - Dupont Circle
I have been going here for the last few weeks since it opened. A very welcome addition to the neighborhood. They have lots of options including loose leaf tea, drip coffee, and espresso drinks. I have been getting non-fat lattes which are great.
The place is a little hard to find, but once you do it is well worth it!
Here is a link: http://www.filtercoffeehouse.com/