We got a note from minnie and mickey in our hotel room (Port Orleans). A bunch of free desserts. Champagne at a few restuarants. Embarassed at a few others (re-enacting "the kiss" for the Whispering Canyon Cafe, pointed out and talked to at length during the dinner show at Cinderella's Royal Table).
We had the buttons and a few people just gave us their fast passes or let us in front of them in line. We also got a few certificates in Epcot for celebration, including a special annoucement at American Adventure and priority seating for that show.
Really, don't EXPECT anything going in and just get the buttons and tell everyone you just got married. They love to at least say congrats!