For many people a holiday in Bali means finding a comfortable hotel and relaxing by the pool. Nothing wrong with that and I have some ideas about the best pools. If you are staying in Tuban you might go to the Discovery which has a nice pool leading onto the beach. The Discovery is a favourite of Australian families and the goo thing about this location is that you will spend minimal time driving and maximum time relaxing. You can be in the pool sipping a cocktail an hour after you touchdown.
For Legian I recommend the Jayakarta hotel. Beachfront location with 3 huge pools, this place was made for splashing around and having fun and the surrounding area is loaded with bars, restaurants and shopping. Needless to say that big hotels have big pools.
Seminyak has the Oberoi, which while not a massive pool will probably be less active with noisy neighbours due to the price. The Oberoi is a very nice hotel.
There are many cute little swimming pools around and you can take your pick. The daddy of swimming pools has got to be the Conrad Benoa. They have a massive lagoon pool that creates a waterway in front of many of the first floor rooms. The pool is only 4 ft deep, but the volume of water is huge.