My boxer is really quiet most of the time. He lets out a couple of barks at my other dog if she lays down in his bed. The only issue we have with noise is when he goes into his kennel when we go out, he sometimes goes a little bit wild making some horrific whining/barking noises (especially when we get home and he sees my other dog run to the door and he wants out) but he gets into way too much trouble if we leave him free while we are out at this point.
He also doesn't bark when people come to the door, but often doesn't notice until they are inside since he is deaf, so that might deter him a bit.
With previous breeds that were barkers I would give them a firm no when they would bark, and would praise them if they remained quiet during normal barking times (like people coming to the door). It didn't eliminate it completely but helped substantially.