Yes, the coffee shop has a lot of bakery items as well as sandwiches, milk, cereal, bananas and some other fruit, drinks, etc.. They are really nice there and let me fill up a cup with half and half to take back to my room so I could use the coffeemaker. Don't get a brownie there though or you will have to get one each night as they are addicting!
The sundries shop, next to the big gift shop in the Marina Tower has bags of pretzels, cookies, soda and some other goodies as well.
In DTD there are a ton of places to pick up stuff for the room as well. We found that the Compass Bookstore right at the end closest to DLH had the biggest bottles of milk for the cheapest prices and they also stayed open later than the coffee shop at DLH.