The 50th will be over by then; however, rumor has it that Epcot will have a 25th Anniversary Celebration. I can see it now, take down the EPCOT sign over Spaceship Earth Geosphere and replace it with a silver 25.
I was thinking it might be the 35th Anniversary of the Walt Disney World (opened October 1, 1971). I would be perfect time since I think the 50th Anniversary of Disneyland is going to end just about the same time (beginning of November 2006). I know that anniversary shouldn't be celebrated as huge as the 50th but it will definitely be mentioned.
CDPA4D - that would be a great idea - silver 25th for Epcot!
If they celebrate WDW's 35th, what would they decorate that in? Isn't 35th anniversary gift coral? hmm.....wonder how they could decorate the World unless they go with Jade (the modern version)? A jaded Mickey? oh no!