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.

I have Elfa ventilated shelves (and some drawers) in my pantry and laundry room both. I love them BUT I use liners so I don't have the wobbly issue going on. That would drive me crazy. Elfa's ventilated shelves, unlike what you can find at Lowe's, HD or Ikea, have the wires a lot closer together. They also "lock" into place so the wire part is sitting really firmly in the bracket - not just a piece of wood sitting on top of the shelf bracket. As far as organizing little things, Elfa has "shelf baskets" that you can put dividers in and stack stuff in if need be. In the pic below, I have one of those on the immediate left (3 shelves up) and above the counter top oven in the back. I use it for bags of baking stuff like chocolate chips, coconut, etc on the left and treats in the back. And I absolutely love their big drawers. Container Store's return policy is great too - anytime with a receipt and the best Elfa sales is 30% off all Elfa products. It starts Dec. 24th and goes through the end of January typically. There is one in the fall that isn't as good - 25% of Elfa Shelving. (No, I don't work for Container Store, I am just a big fan and will be buying some more Elfa stuff during their Dec. sale.) Here's a picture of our new pantry.

I had 18" deep shelves in my old pantry and they were too deep...things got lost all the time and I always seemed to be moving things around to get to other things. The deepest I would go is 15" and even that is too deep for some things. I can fit all my small appliances on the 12" deep shelves except my toaster oven. I put the TO on the floor since it takes up so much space (we rarely use it now, it was bought for and used extensively during our remodel). Even my KA stand mixer (the one w/a lift bowl) fits on the 12" deep shelves. The one caveat I would add is that if your pantry is going to be used for storing large amounts of individual items (like warehouse-sized/numbers), then maybe you could use the deeper shelves...but be very careful to only store the same thing in the space (front-to-back) and remember to rotate items so the back items don't get ignored/forgotten and expire prior to use. I would suggest investing in some organizers to help organize/corral things. But even then I would only want one side to be deeper. I have a "U" shaped basement pantry for overflow/large amounts/numbers but even that pantry has 12" deep shelves on the sides. The base of the "U" has 24" deep shelves, and I have to agree that 24" is too deep.

Sophie Wheeler, you are wrong about the box bay window needing a foundation. It will have an internal seat measurement of 18 or 19" (which is actually useful) and all of this has already been confirmed by a contractor. So, that idea is not an issue. I'm not here to discuss the window. I'm asking for help understanding how I can do a similar idea with a closet type space. geoffrey - thanks. I know I can do a cantilevered bump-out, but I was trying to find out if something on kickers like the box bay window seat is possible. Vith- I don't know the wall colour, sorry.