All of them!
The answer is highly subjective. I have stayed at more or less every resort (except DVC, and ASSp). All the resorts have pros and cons, and where we stay is going to vary widely with what kind of price deal I can get.
During a peak holiday pricing, go value resorts. AoA or Pop, or ASMu. Values also have pluses for efficient transportation, and great food courts. AoA gets bonus for healthy coices. Rooms are tiny though. I find myself making due with no counter space, limited closet/dresser space.
The mods have nice amenities, but they are very large. I put a premium On how efficient my time is spent. I really dislike wasting time on a bus looping around a large lake, or walking forever. Food court at Coronado, not so great anymore.
For us, preferred location room is a good deal, others might need to be in a 'quiet' location. I gain lots of extra fun by cutting out extra resort walking time.
When deals are good, then the deluxes have something great! The convenience, the theming, the larger room, the service. All those add up.
But it also matters a good deal what kind of theming you like. I mean the Contemporary has convenience, but not much theming. The Poly has great theming, but not hot tub. The BWK has great theming, close to two parks, but boy is it a large hotel- in terms of walking around. Love BC/YC pool, convenience to parks. but they don't have a great food court. AoA is very cute, very new. Just not the amenities of deluxes.
Up until this year, I'd also have given a great plug for concierge level at the deluxes. Some folks might find it a crazy splurge- surely one could get a LOT of groceries for the cost off the food offerings included, but club level means food is prepped for you. I would pay almost anything to avoid the nasty refillable mugs in exchange for self serve lattes in real coffee cups! No line, just help yourself. Club level is the easiest way to get the most pure vacation time for your money. The extra staff is a huge plus.
If you like to vacation on a tight budget, it is not for you. If however, your time is precious, and you place a premium on getting the most bang for your time, CL might be for you.