All perks and benefits are subject to change.
Shopping discounts change often, usually there is a shop or two at DtD that give 10% off, like the shop that sells the bath bombs.
There are dining discounts, most are in the 10% range, and are offered only at lunch time or during the week. There are a few 20% discounts, and occasionally a 30% discount, though none currently that I am aware of.
Behind the scenes tours and diving at EPCOT also offer discounts, but again they can change.
There are discounts for water parks, Disney Quest and Pleasure Island, most are in the $4 range.
There are sometimes discounts for Cirque du Soleil La Nouba.
Free valet parking (be sure to tip) is available at the
DVC resort that offer valet parking.
A 25% discount of rack rate when booking DVC rooms for cash through MS, but it isn't always available.
And of course the $100 AP and $125 PP discounts for adults, there is a slightly smaller discount on childrens APs.
The members website give a list of discounts, but it isn't always complete or up-to-date.