We just returned and were gonna skip 1, but got extremely lucky with only 3 1/2-4 days to get ALL of the parks in, including a visit to Disney Quest, Pleasure Island, and a movie at AMC DTD.
I wouldn't skip anything! You can sleep when you get home
My suggestion is to hit MGM on arrival day and hit the major attractions- R&Roller Coaster, Tower of Terror, Indiana Jones, etc.
Make sure you have full days for Magic Kingdom and Epcot, but try to plan those on Non Weekend days since those parks will have the most people. Then, try Animal Kingdom on an early day for about 1/2 the day. We did this one on our departure day since we had a later flight and it worked out perfect! AK has a few great rides (Dinosaur, Primeval Whirl, The Safari, etc.) It's far different from a Zoo cuz you get to see the animals in their natural (kinda) habitat and some you wouldn't see at all in most zoos.
I believe you'll be sorry if you don't get to experience all of the parks and you'll have to come back at double the money once you figure that out.
My vote is to also hit DTD at least one night so the kids and the adult kids can create their own Roller Coaster at Disney Quest. This is also a wonderful "Rain Night" thing to do since it's all indoors. Lots of vertual reality things and simulators that make the experience seem real like Mission Space.
Get Ultimate Park Hopper Tickets- it's worth the little extra to get the complete experience and you won't have to pay to get in Pleasure Island if just the adults choose to take advantage of Parents Night Out and enjoy the 8 different Clubs to entertain you. You also won't pay for Disney Quest, Wide World of Sports, Typhoon Lagoon, or Blizzard Beach if you decide to hit any of them on your trip either.
A late dinner at Bongo's in DTD is a very fun time for the whole family on a weekend, too. It's Cuban Food with a Live Salsa Band with free lessons. The whole place is hopping! The pricing is pretty moderate as well in comparison with Disney Prices everywhere.
Have a wonderful trip- I'm sooooo jealous..... Will you adopt me??