Get the fast passes first, then ride the other rides until you wait for the fast pass time.
This times 100000000. It will save you tons of time and headache.
Rack up on FASTPASSes for high profile rides first thing. Even though the passes have a time frame, you can still go after it has "expired." The only thing that matters is that you go after the start time. This will let you enjoy other rides that don't have longer lines while you take your time going to the main attractions.
FASTPASS Recommendations (if you're focusing on doing the more kid-friendly rides):
Magic Kingdom - Buzz Lightyear, Peter Pan's Flight (this line is a bitch), Dumbo (also a bitch), and Jungle Cruise
Epcot - Soarin'
Hollywood Studios - Run like hell and get a FASTPASS for Toy Story Mania, they'll be gone within an hour of the park opening
Animal Kingdom - Some would say Kilimanjaro Safaris, but if you're there in the morning then just ride it first. It's when the animals are most active.
Other recommendations for not as kid friendly rides:
All the "mountains" at Magic, Mission Space & Test Track at Epcot, Tower & Rock 'n' Roller Coaster at Hollywood, Everest & Dinosaur at Animal Kingdom.
I hope your trip is stress free and full of great memories!