Post on Houzz, with pictures of your space. You will get tons of feedback about your exact space.

OP here - thanks for all of these great ideas. I am going to go with the above advice to do bookcases on either side of a desk. Possibly there will be room for a comfy chair in there but I'll have to see once shelves/desk are installed. I saw in another thread that expedit is being discontinued, so I plan to get those in a hurry I'd like the look to mimic built ins, so do you suggest I go with the white expedit or high gloss white? Maybe I'll have a better sense when I see them in person, but the crown mouldings in the room are painted a a slightly glossy white (typical trim finish - not flat but not high gloss), so I'm not sure which will look better.

I'd go with bookcases on either side of a nice desk. You can use the desk as a bar during family events and dinner parties and as an area for kids to study during other times.

Command center - calendars on the wall, wall files for papers, etc. lots of nice photo frames and/or art

make it a mudroom/laundry room

what about knocking down the wall between the dining and former kitchen? You could still have it a separate 'zone' with couches, etc, but it wouldn't feel so cramped. Obviously, this is a more complicated solution (but if the wall is not supporting, not that expensive).

Our layout is like this--a 9 x 12 kitchen with openings/doors on each of the narrow ends. only the previous owners put a bathroom and mudroom on the back, rather than a new kitchen, so we continued to have a cramped kitchen and chopped up space in the back of the house until we finally knocked down walls and opened up all the space and put triple patio doors to the deck out the back.

We have a similar space that we're about to turn into a butler's pantry, for lack of a better term. Don't let that name limit your thinking. We just want to put in extra cabinets and a closet, not so much for entertaining or bar ware but just for extra everything storage: our kid's schoolwork art supplies and other general stuff that we don't have a place for otherwise.

http://www.ballarddesigns.com/san-marino-secretary-desk-with-hutch/furniture/category/home-office/desks/219676

This one comes in tons of finishes.

I would line the wall with built in cabinets and use for toy and other storage.

http://www.potterybarn.com/products/graham-desk-hutch/?pkey=call-home-office&cm_src=all-home-office||NoFacet-_-NoFacet-_--_-

How about a secretary desk and hutch? With a nice upholstered chair?