Epcot. First park I go to every single time I visit WDW. I've loved it dearly since I was a kid which hasn't changed, although the reasons as to why I love it have changed.
For a while I would have said MK or DHS, but lately I think it's shifted more toward Epcot. As I've gotten older I've started appreciating just walking around the Showcase, having a few drinks, and taking in the experience rather than see how many rides I can do in a day.