Good thread.
As an adult, I've been to WDW three times ('96, '00 and '02). There are still places, however, that are on our list of attractions to see for the first time next time.
Shows: For some reason, we've never seen the Beauty and the Beast show. That's still going on isn't it? We'd also like to see the Little Mermaid show.
EPCOT: We've heard a lot of good things about Cranium Command, so if it's still there when we go next time (looking like spring of '05) we'll hit that one.
AK: The Tree of Life show. I think my wife has always been concerned about the bee sting part!
MK: We need to check out Snow White for when we eventually bring the kids (if the attraction is still there; you never know).
PI: Not really an attraction, but we also want to hit the Adventurers Club. Sounds like fun.
I'm sure I'm forgetting things (and I didn't even mention the number of restaurants we want to hit for the first time). It's one of the great things about visiting WDW, that you can go a number of times and STILL have things you want to see.