There are many places you can use them but we went to The Brown Derby (celebrate a birthday with a free extra desert), Le Cellier (Yummy steaks - Highly recommend the glowing ice-cube float which only counts as the drink.) and Rainforest Cafe (Surf and Turf normally $40 plus the appetizer, drink, and desert, tax and tip.
There are actually about 30 or so restaurants to choose from (in the parks and hotels). I'm sure there is more information on the exact locations on this discussion board or other sources, but these are the places we went and they were all great. (And great values.)
Do your research to find out which restaurants would be the best hit for your family. mousesavers.com & wdwig.com & themouse forless.com were good sources for me.