Originally, in the 80s and early 90s, before we stayed on property, it was always MK first, EPCOT second, Studios 3rd (by the time AK opened we were staying on property). It was just a ritual that we had. I remember back in '91 or '92 when my DH wanted to switch up and go to the Studios before EPCOT, it turned out to be a great idea because it was the day Donald O'Connor was there doing the handprint/footprint thing, so that was really cool. Now that we stay on property (since '97) we always see what park as EMH and go there, and if it's too crowded after away we hop over to another park.