Two places we love:
Fairmont Orchid (Hawaii)
Fairmont Mayakoba
The Orchid has a great beach that our 2 year old enjoyed very much. It is in a lagoon, so there are literally no waves. The cons, well, it is Hawaii and everything is expensive. Food is very pricey, but on the upside, the 2.5 year old eats free. Staff is very nice and there are a ton of families here. Our babe got her own special bead lei at check in, along with a stuffed turtle from the front desk and of course, the nice Fairmont kid toiletry kit.
Mayakoba is a beautiful, family-friendly property as well. There are 4 pools along with the beach of course. The waves are a little big there for a 2 year old though. Mayakoba also offers an all-inclusive option that can be booked or added on (if you are using certs, you'd have to add it on later). Then you don't pay for any food or drink the whole time, so at least you know exactly what you are spending. The add-on price I think is $175/night for adults but the food isn't cheap here either, so easy to spend that much. (you get bills to sign so you see what you would have paid) For this property, IMO, there was no need to leave the grounds at all!
Finally, we haven't been, but in terms of bang for your certificate buck
, the Kea Lani on Maui is all suites. Some day we will try it but have loved the Big Island so much, we haven't ventured over there to stay.