Okay, this is judging from when my kids were 4 and 6. DS was a little more leery of some of the rides. Luckily we had watched some ride through videos so the kids were prepared for the dark rides and pretty cool with them. Anywho, some rides to watch out for:
* PotC -- DD was totally cool with it but the drops freaked out DS a little. They are milder in WDW so you might be fine. I'd probably gauge with a ride through video so the kids don't freak out with the dark, skeletons, and drop.
* HM -- DD LOVED this one with a deep puffy-heart love. I was so glad I'd prepped DS for this one, for the lights going out in the stretching room and so on, and just talked him through it so he did fine.
* Star Tours -- DD was not as keen on Star Tours as we had hoped and I didn't even try DS with that one.
* Soarin' -- they were just eh on this one. DS was a little scared with the feeling of being up high but not horrible.
* ToT -- we aren't fond of drop rides so didn't even try much to DD's dismay.
* Kali River Rapids (kind of same as Grizzly River Rapids) -- DS HATED this ride because he didn't like being wet. DD loved it and wanted to go again. DS has declared he will go on it again if in his swim suit and goggles.

* Splash Mountain -- another thrill-seeking DD loved but didn't even bother with DS both due to the big drop and the water feature.
* Indiana Jones in DLR (similar to Dinosaur in WDW, same ride vehicles and motion) -- DD HATED this one. I mean it terrified her. Whoops. DS was too small. Now DS is huge into dinosaurs so is all over trying this one in WDW.
* Space Mountain -- wasn't sure with either kid so we didn't try.
* ITTBAB -- heard about this one from so many folks, I didn't even bother with this one either.