If you're mostly riding on paved stuff the majority of the time, and maybe a little bit of crushed limestone, grass, smoother offroad, then you may really want to seriously consider a solid front fork bike like the FX or Seek, especially since you already have a mountain bike for offroad. The FX and Seek can handle that stuff fine and would make good commuters. If you want to have a good on road commuter while still having as much mountain bike capability as you can, then the DS or Roam may be what you're looking for. I would ride the FX and DS back to back, as well as the Seek and Roam, and see which you like the best.
If you go with a DS, or Roam, make sure to get a model with a lockout in the front shock. Riding on paved surfaces a lot without a lockout on the shock is a pain and wastes a lot of energy.