We went last fall with my DD when she had just turned 3.
We were there for 6 days, and we went to parks everyday, but didn't stay all day every day.
She loved:
the Main Street parade (the one every day at 3 PM)
the Dumbo ride (it had a LONG line, we got there very early and waited 30 minutes of pure heck...)
the Carrousel (line is not as long as it looks)
Peter Pan
Goofy's Barnstormer
Character Meals
Aladdin's carpets
Jungle Cruise
the spinner type ride in Dinoland in AK
She didn't like:
Small World
Pooh
Pirates of the Caribbean (but she wanted to go on it, afterwards she said she didn't like it)
We used fastpass and never had very long waits. It wasn't a big problem entertaining her on waits because there is always so much to see everywhere. The two most punishing waits were for Ariel's Grotto and Dumbo.
I have no advice for Ariel's Grotto except to say... go to the Akershus breakfast to see Ariel and just don't let your DD see the grotto! Avoid it! (We wasted an hour there we will never get back.)
RE: Dumbo-- get there early. I hear that has a shorter wait during parade times, but we could never try that because she LOVED the parades so much. If she heard the music, that was what she wanted to do. Also re: Dumbo-- have everyone wait together, and then let DD go ride with one adult while the other adult lets people get on the ride ahead of them. After the ride, have the first adult hand off the child to the waiting adult. Just ask the CM first. No one is being disadvantaged by this, because DH, DD, and I have to take up two Dumbos to all ride, anyway. Who cares if we go at the some time or one ride cycle apart? No one seemed to, and she loved riding twice.
Disney is not like other theme parks where we have taken DD. There are no strictly "kiddie" rides there. Everything is for the whole family. So, while it has been our experience at Wildwood and at Busch Gardens that there are "kiddie" rides with very minimal waits, that is not the way at Disney. However, the waiting is really not so bad if you make good use of FastPass and try to enjoy the theming in the waiting lines. OH-- and go off season if you can. We also noticed a HUGE difference between wait times on the first day we were there (Sunday) and the next few days (M-W.)
We took a day and did Sea World. There was little to NO waiting for anything we wanted to do at Sea World and we had an awesome TS service meal there. It was very quiet and laid back after Disney.
The biggest shock for me re: Disney were the waits to be seated for meals. I was floored to have to wait upwards of 40 minutes to be seated. We foolishly got to every ADR 15 minutes early which just made that worse. This year, I will show up 5 minutes early, TOPS. I have blocked out the memories of how we coped with those waits. It was that bad.