I'll put in a good word for Sunset Waters. As mentioned earlier, it is somewhat isolated and a 30 minute car ride away from town. If you plan on spending lots of time in Willemstaad, this would not be a convenient location. Other than that, IMHO, it's a great place to stay for divers and snorkelers.
I spent 10 days there with a group of friends in February, 2006, and we all had a wonderful stay. It's an all inclusive, so their prices include all food and drink...and the food is actually good. It's not an upscale resort, but it is well maintained and the grounds are always clean.
The dive op is first rate with very good boats and exceptional DM's. They are close to most of the best dive sites, including Mushroom Forest. There is a small lagoon right off their beach which provides excellent opportunities for snorkelers. The lagoon also provides access to a decent dive area which usually hosts a couple of resident sea horses.
Sunset Waters, because of its location, may not be the best choice for kids, mainly because it is not as convenient to town as many of the other resorts. They do provide free shuttle service for their guests, however. If you want a very good dive experience, decent food, and can give up some of the amenities of the higher end resorts, I don't think you can do much better than this place.