Visited here during a recent trip to the province and while not completely proficient in knowledge of Halifax's pub scene, I will at least say that Maxwell's Plum has the most taps I have seen in Nova Scotia (regional drinkers may know another).
Located a few steps downhill from the Citadel, which we visited prior, Maxwell's Plum is a pseudo English pub having a large bar area, with several tables and high tops and a floor covered in peanut shells, the aforementioned legume being obtained non-gratis. Anyway, they have at least 60 taps and a very extensive bottle selections that cover Canada and Europe.
For those not familiar with drinking in Nova Scotia: beware the HST tax - about 20% extra. Not a bad place to quaff when in Halifax. A couple of rounds along with a few Stan Roger tunes and you're ready for a night on the town.