DH and I don't plan, but I DO obsessively read the DIS boards and look up restaurant menus, ride reviews, schedule of events, etc. Once we get to Disney, we just do whatever we feel like but will remind each other about things like, "Remember I want to see Alberta Bound some time today!"
We bought Florida Resident Seasonal passes in Oct and have gone 3 times for 3 nights each time since then. If we lived far away and could only do this once a year or so, I'm sure I would do a lot more planning!
But DH and I are kind of laisse faire (spelling?) vacation planners anyway--we like to read up on where we're going and get an idea of what we'd like to do/see, but we're pretty spontaneous once we get to whereever we go.