That is really a tough call. There's so many with pluses and minuses.
I have always loved the Port Orleans French Quarter. We've stayed there eight times. It's small, not spread out, great pool. We drive so the parking lot is close to the room. Buses are frequent and it's the first stop on the line before Dixie Landings so they aren't full. Also the first stop to let off. Food court is good with variety. The only down is the rooms are just a bit small for two adults and two teenage girls and their associated clothing, bathing suits, hair products, and used towels!
The Polynesian is great too. Stayed there three times over the last five years. Love the room size, but wish the sinks were outside the bathroom like in the other resorts. (Teenage Girls again). My wife and I like the quiet pool, the girls like the volcano pool. We always stay in the Tokela building so the quiet pool is right outside the door. Again, we drive and there is a nice parking lot close to the building. Monorail access to the MK is awesome, and it's a quick walk to the TTC for Epcot. The food is great in Ohana and the Kona Cafe, but the Captain's place gets old by the second day. The downs are it's starting to show it's age and the upkeep isn't what it used to be for a resort that expensive. The bus schedules are really hit or miss, seem to have to wait way too long for both the outgoing and pickup buses. Aught to have free wi-fi for what the room cost! (I know, there's another thread already on this).
Old Key West Resort. We stayed in a two bedroom villa 3 years ago. Two families and my 21 year old nephew. Plenty of room, clean, and nice to be able to save a few bucks and time making your own breakfast, lunch, and quick dinners when not eating out. It's an option. Our location was really good near the end of Old Turtle Pond Rd. 100 feet from the bus stop. A five minute walk to the pool. It was the end of the bus line there and took a while but it wasn't bad. We're staying here again in June this year in the one bedroom. We'll see how that works out space wise (two teenage girls again!).
I've only stayed at the Contemporary once, and that was in one of the wings, not the main building. Wasn't impressed, but in fairness I bet it was 30 years ago and I'm sure it's more fun in the main building.
Fort Wilderness Campground 37 years ago! I stayed in a pup tent
enough said. (It really was fun at the time but my tastes have changed somewhat).
Tree House Villas 23 years ago. Three families in the same villa. It was the only way to fly with that big a crowd, but they were nice. I understand they've just opened them back up for guests again.