Having been to WDW 5 times I have some confessions of rides I've never done..
I've never rode space mountain OR the haunted mansion in MK.
In Epcot I've never done mission space or soaring, or much of anything in future world.. before I was on DIS I honestly didn't know there was much to do here other than spaceship earth and test track... I went with my mom and brother all the times when we we're younger and neither of them did much research
In Animal Kingdom I've never did dinosaur or saw FOTLK...
& in DHS I've done most attractions that was my favorite park as a kid so we spent a lot of time there.
SO I have two up coming trips in the next two years and plan to do A LOT of new things! I am going to explore as much as I can, with including all of the items about we'll be doing I am going to
Have dinners at other resorts, also something we've never done!
Go to both
MNSSHP &
MVMCP!
Explore the Epcot Food & Wine Festival (I Love wine

)
Stay in DVC Villas! We've always stayed values.

Take the segway tour around the world in Epcot!
Watch wishes from the Poly beach.
Visit the boardwalk (we'll be staying here in November 2013!)
Do the water parks! At least one!
I'll be sure to add more first time things and must do items as I think of them!

lurking and reading all of your TR has given me all of these ideas.
Now I must put all my attention into where the heck we'll be eating for our newest trip because we only have a month to decided before the 6 month window for ADRs opens up!