I consider my MTB to be my "do it all" bike. I commute with it and have done both road and off-road (rail-trail) touring, and of course using it for mountain biking. I just swap out the tires and add bar ends if I want to do a road tour. It has front suspension and I know most cycle tourers don't think too highly of that, but I'm not concerned about speed/performance when I'm touring and I've always managed to fit everything with just the rear rack. I've thought about getting a true touring bike but I don't see much upside and want to keep my MTB anyway.