We took our boys at ages 3 and 2, then again at 4 and 3, then again at 5 and 4 (and dd at 8 mos), then AGAIN at ages 7,6, and 2. Personally, it depends on your child, but ALSO on how you intend to run your vacation. WDW with a toddler can be WONDERFUL (if you take it at a toddler's pace, at their speed and level) or quite possibly miserable (if you don't). Waiting til they are "big enough" doesn't even mean they will want to ride, either (our oldest ds simply doesn't care for thrill rides). And our kids were ok with the concept that "no, not quite big enough to ride that yet" because there was soooo much other stuff they COULD do. My now 3 yr old talks incessantly about the day she and I alone did our "girly-girl" tour of mk together, complete with princess breakfast, etc. She was barely 2 at the time. My middle son still recalls the first time he rode Buzz LIghtyear -- again age 2. So young kids really do take away lasting memories! My kids had assorted issues at these ages, but we just worked around them to their comfort level (oldest ds did NOT like Eeyore... we simply informed Eeyore at the Pooh breakfast that he was not welcome
.... he waved sadly from a distance! ) One pitfall with a 7 to even 10 yr old -- they don't fit in a stroller, but their legs still get very very tired. You have to figure that their short legs still take twice the steps yours do! It was actually easier at ages 4 and 3 in many respects -- strollers and naps can be a good thing!
And let's also not forget that the 2 yr old is FREE... but Mr. 10 yr Old is an adult ticket (yowch). 2 yr old also doesn't eat as much, and a tiny cooler with some juice boxes and raisins can be a big help... whereas the older child will obviously need (and want) more (like, every ice cream stand, every goodie, every toy kiosk item...you get the idea!)
At toddler ages 0 to 3: it's the awesomeness of it all -- the sheer sight of it all. Take it slow and enjoy it through their eyes! Early nights, perhaps a mid-day nap. A leisurely pace. May or may not freak out with character interaction -- test it out and then use best judgement on whether to get closer or stay at a distance!
At young ages of 4 to 6: Starting to appreciate the rides, deciding what they want to do; typically loves the character interaction, longer park visits are do-able (no naps, potty trained, but still fits in WDW humongo strollers
to allow faster movement around park with less fatigue syndrome) Pretty much believes Mickey MOuse is really a great big mouse.
At 7 to 11: Looking for thrills, possibly, on bigger rides -- can pretty much ride anything they choose. No stroller (you will now need a backpack if you carry fans, water bottles, etc... no where else to stash it!) Mickey Mouse is some dude in a rat suit, but still fun to hang out with. Still wants character interaction. Parents are not yet considered dorks. Better attention spans for shows and interaction-type venues; more appreciation for the "learning" venues (like Epcot, fave park of 8 yr old ds and me).
Beyond age 11: Iffy. May love it... but some "worldly" teens scoff at the "childish" atmosphere. Out of 6 teen nieces/nephews, it was 50/50 -- they loved it or thought it was all so very "beneath" them.
It's so different ( and wonderful ) at every age -- my only advice is PRE-teenager!!
Cindy
Cindy