If you don't have a downstairs office I would do that as long as you can conceal the office mess. We are remodeling and I am doing away with the small open desk in kitchen because my current one is piled high with papers and other clutter. Instead, we already have a downstairs home office where I'm hoping I can train everyone to go with their papers. If you already have a downstairs office or other place for your day to day papers, I'd go with the walk-in-pantry. There are just some things that won't fit in a cabinet no matter how hard you try.

Since you asked specifically about re-sale, I would go with the powder room. Buyers usually pre-screen houses by numbers of bedrooms and baths, so you'll do better with buyers (and with appraisals) with the extra half-bath. While you have all the tradesmen coming through, and if the budget will allow, I'd go ahead and do the downstairs bath, too, (at least walls, floors, elec,and fixtures). If you were not concerned about resale, I'd go with a walkin or stepin pantry. The desk sounds like an inevitable clutter and paper magnet IMHO.

If I were a buyer looking at that style home; I'd be looking for a guest bath on the main level where the kithcen/DR/LR is.

If the guest bath on the main floor is truly accessible as a primary use bathroom, I don't think you need the powder room. Essentially, you already have 4 bathrooms, one of them on the main floor that is rarely used. In a house that size, I would be surprised and disappointed not to find a pantry in the kitchen, especially one that has been recently remodeled. I have a house with similar # of rooms (though more traditional floorplan) and took out a wet bar in the kitchen to get a pantry. It drove me crazy trying to squeeze all of our food into upper cabinets and a lazy susan.

I'd want a pantry. Future buyers can turn it into something else if they want. I assume your laundry is on the main floor?

Thanks for your votes - couple of updates: Room is actually 56" x 56" (a little more legroom for the toilet - not enough for an elongated toilet though);
Laundry is on main floor. Seems like vote is for the pantry. What if we "cap off" the toilet flange and sink plumbing so that it could be turned back into powder room if someone really wanted that? Caps would be hidden by all the shelves in the pantry. Would that be strange?

I think it's a good idea to cap off the plumbing - a plus for future homeowner that may prefer the powder room.

2 bathrooms on each floor sounds like plenty to me!

i'd go for the pantry. if you have no other place for paperwork, I'd put in a shelf at sitting height in there. have a few outlets put in behind it for recharging phones, batteries etc. put a few in/out baskets on it and a file cabinet under one side of it. you could also put a few nicely decorated boxes on that shelf or the one above it for paper 'storage'. (bills to be paid, bills paid).

I'd do the powder room. It's where people want a powder room. That is, in the reception area of the house. When you have a houseful of company, you'll have them using the guest bath and master as well.

I only have the powder room on the main level, and people climb the stairs (they do ask) rather than waiting. Family members don't mind, but others feel awkward.

I know some people make do with one bathroom for a huge family, and lots of people around the world don't have any, but I still vote for the powder room.

You have a good sized kitchen. If you use it as a pantry, what all will you put in there that won't fit in the kitchen?

Unless you're a lover of little nooks, the desk idea sounds like it would become a dumping ground. Romantic in concept, but a pile of junk in most people's reality.

Pantry!

I vote for pantry...and I like the idea of a shelf for paperwork/charging station, so be sure to include an outlet in there. Capping off the current plumbing would be a great idea and cover with a raised floor panel. I have a built-in desk in my dinette and it has never worked well for me. I am trying a coffee station now...but a desk is just odd there.

Thanks for all your words of wisdom. A pantry it is! Shelf/racks for in/out paperwork and outlets for charging also on the list. Plumbing will be capped and hidden but not removed. Thanks again - I'll post pictures when we are finally finished (probably a year from now!!!)
All the best... Diane