I'm not sure if you have flown with both before, but if not, just be prepared for securityand the airport in general. I always warn by hubby - to just know that we will be a security nightmare and that hauling everything through the airport will not a joy. We will prepare for it the best we can but that it is only small amount of the trip and that we should not dwell, but rather move on....its worth it in the end. After our recent trip, he laughed after security - saying that it wasn't as bad he thought it would be (I think I had talked it up so much that he was prepared for the worst!). That said - we had 2 car seats, a double stroller, 2 carry ons, 2 lg checked suitcases in tow - oh and lets not forget the almost 3 yo and not quite 1 yo.
Ditto on taking your time! Plan for naps and know that tired kid meltdowns may happen. We don't even bother with park hoppers and try to encourage naps. Both our pair passed out cold in the stroller just after lunch - dh and I took the time to sit in the shade along the parade route to relax. The boys woke up just in time for the parade and were ready to explore some more. We tried to get them to bed at a decent time and nap so that they weren't tired little disasters

by the end of the week. We took our time and had a fantastic trip!!!!
My kids loved the tiki birds, jungle cruise, the MK train that goes around the perimeter of the park, and toon town as well as the rest of fantasy land rides (dumbo, peter pan, pooh, small world, etc.). We head there first thing in the morning before it gets too packed.
My guys loved character meals - especially the contemporary's Chef mickey. They loved all the character interaction and watching the monorail go through the hotel. They were in awe - so after dinner we took a roundtrip ride on the monorail and saw the castle all light up - they loved it! (They are both crazy about trains.)
Animal Kingdom - Loved nemo, the safari, lion king, dinosaurs, and the animals and scenery. HATED BUGS WORLD - not crazy about the 3d glasses and they spraying of air and water during the show in the dark theater....yeah that one didn't go over well!
Hollywood studios - full size lightening mcqueen and mater were a hit, playhouse disney was great, little mermaid, the honey I shrunk the kids was fun (but a nightmare to keep an eye on them - busy and lots of hiding spots!), and the afternoon parade was great - they knew all the characters.
If your little one needs a first haircut do it at the mainstreet barber - very cute. They give the little one a free pair of ears, a certificate, and wrap the hair with mickey confetti - very cute!
Enjoy your trip with your kids. We can't wait for our return visit in the next month. Can't beat the look of wonder on little kids faces at WDW!