Best island or beach properties to use Reserve card certs?

Have two Reserve cc free night certs in hand and am curious where to use them. We are a family of 4 with two kids 5 & 2. Would like to check out a beach location or an island resort. Not looking to use now but rather over the winter or early spring 2015 months (so looking for a more tropical locale).

Note that bringing kids along with us will rule out couples-oriented Tahiti type locations (unless you think that is a good place to take kids??).

Just gathering ideas for now.

Thanks!