This has been discussed before and you should be able to find several threads by doing a search.
In general, many folks don't have it and say they don't need it. And many folks have it and wouldn't have things any other way. I got the 4X4 option on my new truck and have used it several times on slippery, wet, grass when trying to maneuver in a CG and also a few times in the western states when I had to climb non-paved, rocky roads to get to campsites.
4WD will add a little weight, thus decreasing load capacity, but probably not enough to matter. It will also add complexity (electronics, transfer case and front differential), adds another maintenance item, and probably affects mpg, but not by a lot.
Is it absolutely needed ? No. But I like having it available if I need it, especially that low range. And in case you don't know, a 2WD truck is awful in the snow - no weight on the rear end. It looks like you're in snow country, so a truck with 4X4 would make for a better daily driver in the winter, and I bet would make it easier to sell when that time comes - and also increase what you can get for it too.
* I also got the limited slip rear end. I would highly recommend this option even if you don't get the 4X4 option. Limited slip works automatically (and quickly) - no buttons to push or dials to turn. It works on slippery roads (rain, snow, mud, wet leaves). Think slick, wet leaves on the outside edge of a highway curve.
Tim