Sounds like you're looking to live the dream! We've got a 5-year old kid, so with private school & such in mind, moving to a foreign destination isn't likely. It's fun to dream, though! Looking over other's replies, I'd like to hear more about your hopes & plans.
1.) Second home. How 'second' do you figure? Are we talking living there maybe 3 months out of the year, half-and-half, what? 4-6 months if I had to guess. I'll be fleeing the FL "winter" for warmer climes. LOL
2.) What kind of diving do you mainly want to do? What do you mainly want to see? I used to think living on Bonaire would be the bomb, but you don't see many sharks or much big stuff...how long would it be before, putting love for shore diving freedom aside, you flew off to see large pelagics, etc...? And if you're traveling to dive, why buy again?
my favorite diving is ripping current, coral, and lots of sharks. Bigger is usually better for me. That's why FL east coast diving is my favorite near dive destination, but I do enjoy spearfishing regularly on the west coast by my house.
3.) Are you child-free? I'm guessing so; the lack of requirements for educational institutions & a desire to raise kids in one's home country/culture then are non-issues.
No kids.
4.) What do you like to do besides water sports? Is spending months in a place with no shopping mall where you can't drive an hour straight without flying off into the sea a problem?
Living in FL allows me to indulge in my water activities, but I also enjoy trekking, mountain climbing, white water rafting... pretty much anything to do with the outdoors.
5.) Are you sure nearly 365 days/year of de facto bright, sunny hot summer weather is what you want? Florida glories in being the sunshine state, so maybe so. I love visiting Bonaire, but if I lived there full time it'd get...awfully bright for me.
Year round sun is no problem. I've lived in FL long enough to have adjusted.
6.) Are you at an age (whatever that is) where you anticipate in the next 10 to 15 years desiring ready access to a physician (e.g.: getting on med.s for high blood pressure, high cholesterol, etc...)?
I'm very fit, active, and eat healthy, so aside from injury, I'm not too worried about health issues.
Big question: instead of just looking at a location's pro.s, ask yourself 'What would I miss if I were there 3 months?'
Richard.
P.S.: I like Scubadada's approach. You can make it down to Key Largo for colorful shallow reef diving or deep wrecks, enjoy deeper reef diving closer to home, view the larger animals such as goliath grouper and various shark species close to home, and maybe hit Blue Heron Bridge for a neat mix of critters. Plus it's U.S., with the amenities of home and the U.S. health care system.