One of the spots we also looked at was the Bahamas out islands, especially Eleuthera and Abaco. Beautiful but very hard to get to, especially using frequent flyer miles, and just not as fun or interesting as AC. Not as many good restaurants either.
It's nice to know we're not the only ones who have searched far and near for the retirement/second home place. Our search was more northeast- British Virgin Islands, US Virgin Islands, Grand Cayman, Bahamas(out islands and Providence too.) Connie, I am sure you will have a wonderful time shopping around Belize for your place in the sun. Enjoy the journey no matter where you end up.