I didn't realize I was missing so much! Then again, a lot of the rides I've missed are things that I never cared to ride, unless someone has a reason for me to ride them.
I am sad that I never went on Snow White, Peter Pan, or any of the other Fantasyland dark rides (besides Small World and Pooh, beause my dear mother just adores Pooh). I still intend to go on Peter Pan once the line isn't half my life long, though I guess it's a no-go for Snow White
As for the spinning rides, I remember Astro Orbiter well, but Dumbo I think I did when I was like 11 months old. All the other spinners are really the same to me, not worth the wait.
General attractions... I never do the shows. I saw a lot of the more standard ones when I was little (Beauty and the Beast, Lion King, etc.) but I usually don't have the urge to go see them now. I'm proud to say I think I got almost all of the rides they abandoned at Epcot as well.
Conservation Station and One Man's Dream:
Do them both. Seriously. They're well overlooked but so rewarding. Plus, the Conservation Station is one of (if not the only anymore) places to see Pocahontas. They also have my favorite hidden Mickey in the large mural inside the main building. And like many have said, One Man's Dream is a must for any big Disney history buffs. I could spend HOURS in there, but when I went last I had limited time. It's a lovely tribute to Walt, and do stay for the video at the end because it just made me smile.