Hi Jennifer:
This question has many correct answers and may depend on the makeup of your party. I think Animal Kingdom Lodge is the best Resort, especially if you reserve a savanna-view room where your family can watch the animals walk by right outside your window. Upon entering the Animal Kingdom Lodge, your family will be mesmerized by the dramatic lobby expertly themed and filled with African artwork, artifacts, a fireplace (at Jambo House), and huge windows. The pools are great at Animal Kingdom Lodge. Animal Kingdom Lodge Jambo House is home to the 11,000 square foot Uzima pool. The pool boasts a 67-foot slide as well as a tyke-friendly wading pool area. Not far away is a kids playground. There is also Pumbaa's Fun and Games Arcade. Animal Kingdom Lodge Kidani Village is home to the wonderful Samawati Springs pool and kids water playground. As you check in, request an activity guide from the front desk for a schedule of organized activities. The Resort is home to a children's activity center, Simba's Cubhouse. The downside is that the Resort is located somewhat far away from a number of the Parks.
I also have a soft spot for the Contemporary Resort, one of the original Walt Disney World Resorts. I still remember the wonder I felt as a six-year old staying at the Contemporary Resort and watching the monorail run right through the A-frame Tower and marveling at the lobby's 90-foot, floor-to-ceiling ceramic mural created by Disney Legend, Mary Blair. Also, the Grand Floridian Resort and Spa is considered by many to be Disney World's most magnificent, luxurious, and picturesque Resort. Both Resorts are on the monorail line, which is convenient for transportation. I also enjoy the Yacht and Beach Club Resorts. Their pool, Stormalong Bay, is considered to be the best on property, and the Resorts are centrally located and within walking distance to Epcot and a long stroll away from Hollywood Studios.
Enjoy your vacation.