Polynesian, Club Level, Theme Park View. Hands down. Here's why:
Theme: The resort like it's own little island vacation within your Disney World vacation. The Poly is great for letting you escape and making you relax (if you let it). The tropical atmosphere is insane.
Location: The MK is easily reached via boat or monorail. Epcot is easily reached via the TTC monorail which is only a short walk or resort monorail ride away. The CR and GF being on the monorail loop opens up multiple, excellent, easy to reach dining options.
View: The view from the CL TPV rooms is nothing short of stunning. IMHO it's the best view on property. Being able to watch the entirety of Wishes (with it's reflection on Seven Seas Lagoon), with music, from your own balcony while munching on snacks and beverages from the lounge is just priceless.