I have found Bowe's Office Equipment to be very helpful to me whenever I came in to ask questions or advice about something they might sell. They have a good selection of office supplies and equipment, plus some computer-related things too. It's also a good place for things like envelopes and stationery.
We used to bring books here to sell or trade before we knew about other bigger stores like 2nd Look, and it was a lot more convenient to get to since it's on North Division and we were coming from the north. They don't have a lot of selection, though, and won't let you use credit on all the books they have for sale.
Auntie's Books is a nice bookstore downtown. They carry mostly new books - can't remember for sure if they have a used section or not. It's a nice building and location, though. It seems like it would be a nice place to spend some time looking for a good book to read!
2nd Look is a good place to bring used books when you want to sell them or trade them in for others. I've found that they take a lot of books that other bookstores wouldn't, and I think they pay about a quarter of the cover price in trade. Realize in advance, though, that you usually still have to pay a small amount in CASH per book even if you're paying with credit.
PROS: relatively big selection
CONS: can't buy books with credit alone
The QFC is basically just a big regular grocery store, but they do carry a few things I like here that are better deals than most other places - a certain brand of you-bake french bread that comes in multigrain too; good selection of bulk teas (upstairs where the bulk/organic foods are); and unfortunately not the Kalani coffee or packs of Turkish coffee that I used to come here for when I was in the area.
Ralph's is an OK place to stop in at when you're in downtown Seattle for business or something, but it seemed a little like most of the things they carry are marked up from what you'd find at other grocery stores. They do have a pretty good deli, though, with good pizza. Unless you live right nearby this is probably going to be just a place to come when you find yourself in downtown Seattle and need something to eat without going to a restaurant.
Tenzing Momo is one of the little shops in the shopping area around the Pike Place Market and they specialize in things like incense, essential oils, herbs, and related books. It's a really good place to find any of those kinds of things as they carry a good selection of good quality things.
Paper Zone is probably the best single store to come to when you're looking for paper to use for some kind of project, or just as stationery. They have rows of different paper styles, and most are available in different weights and in packages of 50 or 100, or by the sheet. If you look long enough you can usually find at least one good type!
This is a small shop but very high quality. It's right downtown, and they carry only upscale items. There did not seem to be quite as many varieties of paper as I expected, but what they did have was all nice. They carry stationery, art cards, envelopes, and also calendars, wrapping papers, and other paper-related items. Prices are not cheap but are generally reasonable if you need this kind of quality.