My wife and I went to WDW on our honeymoon last October. I will recommend against wearing the bride and groom mouse ears. We received buttons that said "Just Married" that were just as effective in getting us free stuff and best wishes without looking ridiculous and without being associated with some of the people who wear those ears. Most of the people we saw who were wearing the ears were loud and obnoxious about their honeymoon. No offense if anyone who reads this was honeymooning last October and wearing mouse ears, but it just wasn't our bag.
I will give you the (mostly) comprehensive list of free and otherwise nice stuff we got during the honeymoon:
1. Free dessert at California Grill, Shula's, Coral Reef, Raglan Road, Restaurant Marrakesh, and a bunch of counter service restaurants.
2. Free champagne and strawberries at Hollywood Brown Derby in lieu of free dessert (we were on the Fantasmic dinner package).
3. California Grill decorated our table.
4. 'Ohana placed us front and center for the evening's activities and we participated in the show.
5. Coral Reef gave us a personalized menu.
6. The Norway boat ride operator gave us a boat to ourselves, which was pretty cool. Same thing happened at Small World.
7. WDW Dolphin gave us champagne, etc.
8. Enough "Congratulations!" from CMs to last our entire marriage.
I would recommend eating at California Grill one night when they're doing Wishes at MK. Tell them in advance that it's your honeymoon; we got a sweet table for viewing and they decorated it nicely and really made us feel special. The fireworks are also good.