This thread is shocking! I can't believe a bunch of Disney-philes such as ourselves can produce such an extensive list of things we've missed.
I feel better about myself knowing that I'm not the only one who has missed out on a couple of rides:
Davy Crocket Explorer Canoes
Mickey's House in Toontown
Gopfy's Bounce House
Chip n Dale's Acorn-thingy
and I've never seen Big Thunder Ranch. Does that even still exist?