I would definitely go with the Mossberg 500. They are a fine shotgun and also the availability of extra barrels for them are easily acquired. For example a full choke barrel for ducks and geese and a Modified or Improved Choke for bird hunting and even a rifle sight barrel for Deer hunting and defense purposes. All at a decent price~
Just a great all around gun for the money. I have owned two 500s which I gave to my children. I presently own a Model 930 Turkey Camo Semi Auto Mossberg. Can't go wrong with Mossberg!