Let's start with the fact that all WDW resorts are fun and worth a stay. However, although I love staying at them, I would NOT stay in a monorail or Epcot resort for a resort only stay. That is mainly because the theme parks are so close by that I would be sad not to visit them. What type of stay are you looking for? Do you want a villa with a full kitchen and room to spread out? Or are you looking for a more romantic trip with dining out frequently and lying in the sun poolside? Besides those considerations my choice would depend upon my budget and theme preference.
If doing a value, I would stay at ALL Star Music. It is in the middle of the other two so it is easy
to take advantage of the offerings/pools at all three AS resorts. The All Star is classic Disney in many ways and is also a good choice with small children.
If my budget had a bit more flexibility, I would stay at POR. There are lots of activities there as well as a sit down restaurant. It is spread out so walking around the resort is pleasant. Also, you can walk to POFQ or take a nice boat ride to Disney Springs for. further shopping and dining options. You have three styles of room available to. choose from, as well.
If this is a splurge visit and the visit runs to deluxe resort prices, then my first thought is the AKL. The theming here is perhaps the most spectacular of all the WDW resorts. There are many activities to take part in and the dining choices are incredible, with some of the BEST of all the WDW restaurants to enjoy. You also have a choice between a villa at Kidani or a room at Jamba House. This would be my personal choice for either a family (Kidani) or a romantic (Jambo) resort only stay.
All the other options that folks have listed already are really great as well. As I read them, I generally thought "Yes. That's a good idea". So, it is really personal preference, the style of the desired vacation and the budget that will help frame up the decision. There is one other factor that I would consider: unusual conditions at my chosen resort. Is there construction or a conference or a large group of unsupervised teenagers expected at my resort during my planned stay? Will the main themed pool be closed for maintenance? These sorts of disruptions can significantly impact your stay at any resort. Just something to check on before you choose your resort.
Enjoy your visit!