Kidcot, definitely!! My kids (even my 2 yo) enjoyed the Kidcot stations! Living Seas was another big hit as was Spaceship Earth. My kids are not fond of the 3D effect shows (such as Bug's Life, Honey I Shrunk, etc.) So if your child is a bit sensitive, this might be something to wait until he is older.
I polled my kids as to what to do at Epcot and they said:
1. Living Seas
2. Ellen's Energy Show
3. Spaceship Earth
4. Viking Ship
5. Character Greeting at the countries
6. The train at Germany (train display)
7. Rio de Tiempo (ride in Mexico)
8. Fireworks (Illuminations)
9. Tapestry of Nations (now Tapestry of Dreams - Parade)
10. Riding the Ferry across the Lake
My kids were 8, 5, and 2 last trip and that is from their memory!
Have fun! Epcot is my favorite park!
51 more days!