Three speeds are more versatile. They are also more expensive to fix than SS. Ride both and see which you like best. BTW since it's a Shimano Nexus 3-speed the shifter will be one of their Revo models, otherwise known as a "grip-shift".

Another bike you may want to consider that's in the same vein is the 2010 Kona Worldbike: http://www.konaworld.co/bike.cfm?content=worldbike. The 2011 model changes to an aluminum frame (and is called simply "Bike") so you may be able to pick up a 2010 at a discount.