You may want to consider a touring bike as your commuter. The Surly Long Haul Trucker, Kona Sutra, Trek 520 and others are all popular choices. Compared to a cross bike these are going to have a more relaxed geometry (including an upright riding position) that's going to be comfortable for riding long distances instead of going fast. Typically they'll also have more braze-ons for attaching racks, fenders and that sort of thing, and are better at carrying large or heavy loads. They come with wider tires than a road racing bike, so like a cross bike they will be good for light trails as well as roads.