Ha.
Well, of course the devil is in the "only one store" and once you include online versions, then that allows access to enormous amount of goods (I mean, it's almost hard to think of Nordstrom on-line as "one store").
Shoes are the problem...
While working, I'd have to say, (aside from shoes) that the Mothership, AT, would win. That's not because of haute style, but because I can reliably get work pants and skirts that fit better than any single other maker or even most makers, and the variety of tops is large enough that over time, some form of classic + trendy is possible. And probably could find something in a jean and casual pant, though those have not been as good for finds.
For really using "one store," I'd need a department store, for soup to nuts wardrobe items, if that's the restriction.
I could say Dillard's, because it has many different "sub-boutiques" of varied brands and designers, and some well-made items as well as more affordable items, and of course a shoe department, and I can try things on, and if I were totally limited, I'd go with a place I could try on things IRL whenever I wanted to, maybe even over a humongous online source.
For an online source I'd go with Nordstrom and do the Sears Roebuck thing, live off of mail-order, and order a crateload of stuff several times a year to try on and just return what didn't work.
