I like the idea of either a cyclocross or touring bike. Either of these will support racks, wide tires with room for fenders, and drop bars. For myself, I chose the Surly LHT complete bike, because I am far more likely to do a little loaded touring than enter any cyclocross races. Besides, I already had a decent road bike and mountain bike. I had used the road bike a little while for commuting, but didn't really like the backpack either. Plus, I didn't have room for wider tires and fenders and rack on my road bike.

Good luck with whatever you choose. If you were lucky enough to find a used Surly Crosscheck or LHT, or a Trek 520 or Fuji touring bike, you'd be all set.