I come back because I have such a blast with my 22 year old son at the parks (WDW and SeaWorld are our favorites), offsite accommodations are such a good value, it's the closest and cheapest warm place for me to get to, I'm not a beach person, so it gives me something to do in warm weather, my extended family enjoys meeting up here, my nephew lives in Orlando so I get to see him, my cousin lives in Tampa so I get to see him, and it's a super easy trip to plan. Do note: I normally go once a year for just four nights/three days -- one resort day, one SeaWorld day, and one day at one of the Disney parks. -- just a little mini trip, so I don't get too burned out on the place going there again and again.
Not sure if I'd like a longer trip or not -- prefer short I think. Maybe a factor is that DH doesn't like Orlando, so stays home and I like to save some vacation monies for other trips that we do with him each year and keep Orlando as a short / budget trip.
At the parks though I always have a Zippity Doo Dah day