Just finished a monster project at work and now I want to relax with my little ones (age 18 months and 4.) Any suggestions for a family friendly place next to the beach in the $150/$200/night range. In general we like a little adventure (last trip was to Costa Rica) and this time around I was even considering an all inclusive just so we could do nothing but relax and build sand castles.

Look into DR. It's the only place on your list that you're likely to come close to your price range for an all inclusive.
The other islands are relatively expensive.

Mexico is another option.

I agree.. or Playa del Camen, Mexico could come close to your budget, especially with AI you will have to go higher on your price...

Your budget is quite low and borders on unrealistic for an AI resort for 4 people even if 2 are children staying in the same room. You are budgeting a maximum of $1,400 for a week's stay - that's difficult for 2 adults let alone adding two children. You are going to have to make many concessions regarding location and quality of your accomodations.

As others said, look at resorts in the Dominican Republic, Cancun and Playa Del Carmen - they are traditionally the lease expensive destinations in the Caribbean.

I can't give you specific hotel recommendation but suggest you look at "package deals" that are often advertised in the Travel Sections of many Sunday newspapers, and online travel sites like Travelocity, Expedia or Orbitz and perhaps some of the websites of airlines that service your nearest international airport. You may get lucky and find something within your budget.

I noticed you tagged your post with certain island destinations. For what it's worth forget Grand Cayman and Bermuda - those are relatively expensive destinations. Antigua is more moderately priced but still, on average, more than the Dominican Republic, Cancun or Playa Del Carmen.

Thanks for the advice--Sorry I was not clear. The 150-200$/night I meant for accommodations only. I am not sure about the AI or whether to try for a cabana or hotel.