The craft beer movement is in full effect in Rome and small pubs and beer shops have cropped up all over town. Some are more serious than others and not all are worth a dedicated trip, but Birra + has been holding it down in Pigneto since 2009 and I routinely head there for my favorite hoppy New and Old world brews. In October 2012, Birra + became twice as nice when it opened a second location, in Garbatella.
The new location is a bit smaller than the first, but equally worthy of a trip outside the city center. Expect the same array of quality bottles that will please any beer geek. There are only a few stools inside, so be prepared to stand if you want to drink in the shop, or buy bottles to take away.