Hi David,
If you are choosing for boys in that age range you have to take them to Animal Kingdom. Epcot is wonderful, and one of my favorite parks, but it's really not going to hold the interest of those boys for long. I'm not saying they wouldn't like it, but it really is geared more towards older kids and adults.
Animal Kingdom has been my son's favorite park for as long as he can remember. I've been taking him to Disney since he was 3 months old (he's now 10). Kilimanjaro Safaris are my family's favorite attraction because you get to see the animals up close, and each time you ride it's a different experience. Do this one early in the day when it's cooler or towards park closing so you get to see the lions.
There are so many favorites on our list, and I don't have enough space to list them all, but please don't miss Conservation Station, Affection Section, DINOSAUR, or Kali River Rapids. Here's a
link to see more attractions.
You are in for a wonderful day filled with fun and excitement that you and those boys will never forget!