Hi Connie,
I love spending my dining plan snack credits, especially on more unusual items. As a general rule any single serving item under $4 counts as a snack credit, also look for the purple box with DDP and a picture of a cup on it next to menu items.
Some of my families favourite ways to use our credits are -
Magic Kingdom - DoleWhip at Aloha Isle, a delicious pineapple soft serve float. Funnel Cakes from Sleepy Hollow. Ice-cream sundaes from Mrs Potts Cupboard. Ice-cream sandwiches, french toast, cinnamon buns etc from the Main Street Bakery and any of the delicious candy including fudge from the Main Street Candy Store.
Epcot - Lots of goodies from the countries around the World showcase including school bread from Norway, egg rolls from China, crepes from France and Kaki Gori from Japan.
Downtown Disney - the make your own treats from Goofy's Candy Company
My girls also like to use credits to buy the big lollipops (suckers), special candy and character cookies. These can be found in most resort shops.
You can see a great unofficial list of all snacks on
www.disboards.com go to the restaurants board, click on dining plan and you'll see a thread right at the top called 2009 confirmed snacks. As with all things though things do change so be sure to ask if it qualifies as a snack before you buy!
Happy snacking,
Jo