A lot of that depends on personal opinion and how much you want to spend. These are my personal favorites-
Value Resort- Pop Century, it's newer and nicer than the All Stars and it's also closer to most of the parks and Downtown Disney.
Moderate Resort- Caribbean Beach or Port Orleans French Quarter. Caribbean Beach is nice and they have recently updated a portion of their rooms with a pirates of the caribbean theme (I just stayed there in Oct.) they have pirate ship beds that are pretty cool. They also have a brand new pool area. French Quarter is cool because it's really well themed and the food court has beignets. Yum.
Deluxe Resort-Animal Kingdom Lodge or Polynesian. Animal Kingdom is a beautiful resort and has balconies in the rooms overlooking the savannah area with Giraffes, zebra, and other african animals right outside your room. It also has Boma, which is one of my favorite restaurants on properties. It's an all you can eat buffet that features foods from all over Africa. The Polynesian is also great. It's one of the older resorts but that adds to its charm. It has a very retro polynesian theme, it's on the 7 seas lagoon and has a beach and it's a monorail hotel which makes it really easy to get around the property. It also serves amazing sticky wings at the bar and at Kona Cafe in the lobby.
Like I said, those are just my picks. All of the resorts are nice and you really can't go wrong.
It depends on your budget. The value resorts are fun. You can choose which theme you would like. A con is the value rooms are a bit of a walk to the disney buses. Next up is moderate. Slightly better rooms and pools. These are a little more expensive than the value resorts. The deluxe resorts are the resorts that really stand out. Most off a view of the Magic Kingdom, great pools and monorail service. One over looked option is Ft. Wilderness campground. They have great cabins(or tent sites) and water taxi directly to the magic kingdom.