Muku's bar next to the daladala stand is the liveliest of the bars in town offering all you would expect from a Tanzanian bar.
Hiphop beach next to the long distance bus stand will be a cracking place for a drink overlooking the bay if they ever get round to getting a beer fridge. Currently they have cold soda and warm beer.
Ten Degrees and the Boma listed in the sleeping section are fairly standard ex-pat bars.