THE Ultimate W. Caribe Resort for Small Children?

Looking to take a family vacation next year with what will be a 3 and
4-year old. Budget is virtually unlimited but we don't like to feel
like we are getting ripped off. We like luxury resorts without being
stuffy (no dress codes, etc.). Other requirements would be:

- Must have a kids program for at least down to ages 4, preferably 3.
- Must have reliable/reputable babysitting service.
- Must have an excellent pool area with kids pool and water slide,
etc., a big plus.
- If a beach destination, must be on a nice swimming beach with warm
water - clear blue water would be a big plus. (We are NOT considering
ski resort destinations, or amusement park (Disney) destinations for
this trip.)
- Must have some character/cultural draw to it. (We are from Seattle
and like to travel to new, interesting places with lots of
activities.)
- Must be relatively easy to get to from the West Coast (Seattle)

We are considering Florida destinations like Sanibel and Captiva
islands, Key West, Key Largo, but we don't really see a lot of
cultural draw there so we would consider Caribbean destinations like
Caymens, Jamaica, Mayan Riviera south of Cancun, Ixtapa, Los Cabos.
If few resorts we have on our list include Xpu-ha Palace and Grand
Scaret on the Mayan Riviera (although not sure if we will be up for an
hour car ride after flying all that way?). There's a bunch of
Iberostar resorts but I can't see to distinguish the pros and cons
between them. In Cabo, the Villa Del Palmar, Villa La Estancia, and
Hilton Los Cabos all sound like they could foot the bill and they much
more easy to get to from Seattle than the other places. Club Med
Ixtapa actually is no farther than a flight to Caymens or Jamaica so
we would consider that too.

Your comments on these or other resorts you think would fit the bill
are much appreciated.