If you are staying at POFQ you can get the best breakfast on property very easily for just a snack credit: 6 big, fresh, piping hot bignets covered in powdered sugar. Best deal on property and only a snack credit. Another good use of a snack credit is to get some of the pastries in the French Bakery as you're leaving Epcot one night, put them in the room fridge, and use them for breakfast the next morning.
As far as using a CS for breakfast the CS over at the Poly has tonga toast, the Main Street bakery has good CS breakfasts, and Wolfgang Pucks Express in DTD has the best corn flake coated French Toast with fresh fruit on them.