My husband and I are connoisseurs of Indian food, and are always looking for a new place to try. Our current favorite is India Express (B'way and Republican) in Capitol Hill. It doesn't have much in the way of ambience, but the food is wonderful, relatively inexpensive, and the service is fast and friendly. Their curry mussels appetizer and malai kafta make me swoon! (Get extra naan for the sauces, and order their homemade achar - lime pickle.)
Tied for second are Banjara (Queen Anne Ave and Boston) and Bengal Tiger (just north of 65th on Roosevelt in Ravenna). Banjara is a little pricey, and the portions aren't as generous as India Express, but the food is very good. Bengal Tiger has great samosas, not a disappointing entree on the menu, and excellent service.
Other fallbacks are Chutney's (Wallingford and Cap. Hill) (reliable, but not spectacular), Tandoor (53rd and The Ave in the U-District) (they've left out something every time we've gotten take-out).
Anyone else out there dreaming of vindaloo?