I'm an all-park junkie. If I go to WDW for two days, I spend half a day at each park! I can't stand going to Orlando without walking through the gates of all four WDW theme parks, though I have done it once -- I had to miss the Magic Kingdom because we were staying close to Epcot and MGM and had a reservation in AK It was SO sad to be in WDW and not see the castle!
I'm guessing that if you go often enough, it becomes more comfortable to miss a park now and again.
May 2008 CSR