99% of people here (including me) will tell you that SAB is by far the best pool on property, but if Beach Club/Yacht Club is not an option for you, here are some other ideas...
Boardwalk: Many complain because this is the "Clown Pool," and I had an irrational fear of clowns as a kid in the 80s that follows me somewhat into adulthood. That said, this pool doesn't scare me at all, and I find it rather whimsical and fun. It's in a great setting, where the old-timey circus/carnival theme works well with the look of the resort surrounding it, the pool bar (which looks like a circus tent), the Dumbo tiling around the edge of the pool and the slide which is actually my favorite slide on property. Also, for some inexplicable reason, we find the pool at BWI to be the coolest (temperature-wise) around. We highly recommend it.
Swan/Dolphin: What a GREAT pool! It's not overly themed, but it feels exclusive, big, the slide is great, and I love the waterfall effect. Pool bars flanking it are great too.
Grand Floridian: Another not-overly-themed pool, but great none-the-less. The Grand behind it paints such a gorgeous backdrop, and again, the waterfall is splendid. The quiet pool in the middle of the resort is just so huge, and feels nice and roomy. It's particularly lovely at night.
Contemporary: The main pool and quiet pool at the CR are boring and feel the most like bathwater due to there being no shade anywhere. The pool at Bay Lake Tower however is great. Awesome slide, visually appealing, and not terribly crowded as it's for Bay Lake Tower guests only.
Polynesian: The main pool is cool with a great view of the castle, but PACKED all the time. The quiet pool is much more relaxing, tropical feeling and again, really lovely at night.