Family vacation: disney, cruise, or AI?

[juliahenry]

We're planning our first family winter getaway with actual activities. In previous years, we've just gone to Florida and hung out, now we want to do something a little more organized.

-kids will be 8 and 4.
-dh and I want some kid-free time each day, so either a kids' club or similar activity (this is new for us, we haven't done it before because kids were too young to fully participate)
-we want to spend about 5 days doing whatever we do, not including travel time
-budget is about $4500, including travel. But I am cheap and would be happy to spend less
-Time is late Feb/early March
-oh,and dh and I really don't drink much at all. So AIs with tons of free booze don't appeal

-we want to relax, with occasional sightseeing/activities.

so far, we're considering:

a disney cruise to either the Caribbean or bahamas
a different cruise (any recommendations?)
driving to Florida, doing a day at disney and then going to the Florida club med for 4 days 
An all-inclusive family place somewhere in Mexico or similar. (Suggestions?)

are there any websites that would be good places to look for trips and ideas?

please help me find something. Because this is new for us, I don't really know where to look or what we should do. Thanks for any suggestions!