Mossy 500/590, Mav 88, Rem 870, Benelli, Saiga etc, they all serve a purpose - HD.
Go to your LGS and check them all out. Hold them, play with them, and see which one you like. I dunno what your price range is but that might have something to do with your decision also. Then buy a few cases of ammo and your all set!
If I were you, Id just go with a 500. Easy on the wallet, very reliable (like most shotguns), and that extra money saved can go to cases of ammo.