Do I have to choose just one?
I had a hard time answering your poll; I have an 870, an 870, an 870, a Norinco HP-9, and a Benelli M4. Plus the SxS's and singles . . .
My Benelli M4 is certainly the best shotgun I have ever had for all the other factors, including reliability/weatherability, quality overall and it is the ultimate in Tacti-cool


, but the price means I am not going to be tossing it in the back of the truck without a case . . . and when my father and I were hunting this fall and he fell (carrying my M4!

) it was all I could do to make sure Dad was alright before I picked up the shotgun and checked it over . . . I honestly didn't hesitate to help Dad, but that little voice was crying out to grab the M$ . . . and I let him borrow a SxS coach gun now.
A semiauto will always get you the fastest and most accurate second shot and follow-up shots, as you never have to take the weapon out of line to rack the slide. With a little practice the Benelli can double-tap slugs with a 2" separation! (And it only cost me two boxes of slugs to find that out!) On the downside, Barrel length with any semi-auto is going to be at least 18.5" and your magazine capacity will be limited to 5, both by

legislation.
The 870 is the ultimate tuner shotgun, you can accessorize it, hunt with it, get the gun and parts relatively cheap, buy a used one and make it your own . . . whatever you want. Resale is not hard as there's lots of 879 fans out there. No limits on barrel length or capacity. With practice you can rack it and take your second shot quickly and accurately -- if you need one! I currently have an 870 slug gun with a scoped, cantilevered 3" magnum rifled barrel

, an old 870 Wingmaster I got for a hundred bucks years ago and still play with, and my shorty with the Dlask 8.5" barrel

. And a Norinco HP-9 which can interchange parts, barrels and accessories with the other guns. Between these 870s and my box of parts and accessories, it is better than Lego: a new toy every day!
I have to agree with josh -- the Norinco HP-9 is the best value-for-money shotgun I have owned. If you start at cost and make allowances for your other factors then this is a clear choice for a first shotgun. It simply has all the advantages of the 870 pump and the cost is unbeatable. And by the way, it is the gun Dad would have been carrying if his shoulder let him rack the slide easier . . . like a good used car it is useful but I don't care what happens to it, even new out of the box.
I have owned Mossberg and Winchester pumps, nothing terrible to say about them, but I chose the 870 as my goto gun for all of the purposes you listed. It works for me.
All that being said, why would I limit myself? You are obviously choosing a first shotgun. Guarantee you it will not be the last one. I personally haven't tried a Fabarm yet but i have heard great things about them. Dominion Arms products look good for the price. The Browning pumps and autos I have seen have marvelous fit and finish and good features for the shooter. Hated the Maverick with the curving barrel that I didn't buy at a gun show, but they might have better QC now . . . damn, now I have to go fondle

, I mean clean and maintain my shotguns and maybe go down to the local shop and see what they have there. Wouldn't want to get stuck in a limited mindset and deny myself another great shotgun . . . Now I'd like to look at a Fabarm, heard they had one in . . . need to start scheduling more overtime again!