Georgetown is still my favorite place to go, but for brewpubs and Metro accessible places I recommend going to the Rock Bottom Brewpub in Ballston Common Mall (accessible by the orange line Ballston stop). It's right outside of DC and a cheap metro ride. They have the best beer and food out of the three brewpubs I've been too, plus they give AHA discounts.
Capital City is really good too, but they don't take AHA discounts. Gordon Biersch is there as well and takes AHA discounts, but in my opinion their food is overpriced to quality & quantity and (more importantly) their beer isn't all that great.
But to reiterate, goto Rock Bottom. Good food, good beer, and good prices. They have the cheapest flight/sampler prices out of the three.
I was in Gtown for the 4th and really with the exception of the great restaurants, Adams Morgan bar scene is the best place for diverse beer choices, unless you go to a brewpub.
I'm attending grad school in the area and I've been trying to get to every major drinking location that I can.