The baguette's at Firehook are very good. I bought a baguette at Atwaters (Dupont Market) and it was dissappointing comparatively. The Paisan (I believe) is sold at area Whole Foods too. No needs to go far away!
while it is not firehook, i have found that harris teeter has a pretty darn good bakery for breads. their baguette is more than serviceable: crusty exterior, soft interior (if a little on the large side). excellent with that nice lurpak butter sold nearby!
monavano, also try the cranberry walnut bread! dense, just a wee bit sweet, with nicely acidic (but not too tart) cranberry pieces and large, savory, and fresh walnut pieces. toasted.....mmmmmm mmmm good! sinful with unsweetened butter!
Breadline's on Penn between 17th and 18th. BL and Marvelous Market are the two best in the area . . . crusty exterior and fine, flavorful/breadlike interior. Both are the real deal. BL also available at Snider's in Silve Spring.