If you can only afford to go to a vacation destination once...

[EKW]

Split the difference...plan a trip for when the baby is 4 (or within a month or two of it.) At that age he/she will be able to appreciate Disney for being Disney. Kids that age know the characters, the shows, the songs, etc.

My opinion is that, until kids are around 4 or so, the trip is more for the parents than for the kids. Not that a 2 year old won't enjoy the trip, but he/she would enjoy a trip to your local amusement park just as much.

At 12, your oldest should still be willing to be around you (although, I will say, not all teens hate spending time with their parents..my older son still loves to do Disney with the family) and should be willing to do most of the rides. Your middle child will have the benefit of having the family doing both big and little kid stuff...he/she can enjoy whatever appeals to him/her.

Not that your 4 year old will remember the trip, but really, look back to when you were 12. How many details do you remember from back then? Plan to do scrapbooks that tell the story of your trip and your whole family will have memories to save!

BTW...40 really isn't the end! I've made it to the doorstep of 50 and can still haul my old feeble self through a week of Disney!