Atlantis is a really cool and generally unnoticed little bar. It has great deals with for local brews and a raw atmosphere that's been dwindling in the Fishtown nightlife. Another great Philly bar where your friends with real jobs can drink great micros while your friends with...less good...jobs can enjoy a nice city wide special.
Pros: relatively undiscovered, nice selection for all budgets
Cons: kind of hard to get to from a lot of the city