We've been building most WorkCycles bikes with Shimano's Nexus 8sp hub for almost ten years. It's strong, smooth shifting and very low maintenance. The range is wide enough for even riding a loaded bakfiets in mildly hilly terrain. The thick aluminum flanges support the spokes well to build very durable wheels.
As of 2014 we use exclusively the Premium version of this hub that features better quality bearings and sealing. The Nexus Premium is internally identical to the Shimano Alfine 8sp hub.