Just a note: Unless it's a medical degree, the best warm-water diving doesn't often mix with demand for advanced skills - not a lot of rocket science going on around Apo Island, Phi Phi Lei, or Songo Songo!I'm looking to relocate somewhere.. permanently.
-I'm an American. I have a 9-5 job & specialized advanced degree that should make it relatively easy for me to get a visa (and eventually, permanent residency) most places. ...
-I'd like to relocate somewhere with great land-based diving (if I can teach on wknds, great). I like big marine life (Seals/Sea Lions, Whales/Whale Sharks, Dolphins, Sharks, Mantas, Manatees/Dugongs, etc.) and healthy coral reefs. I like cave diving too.. but I'm not overly big on wrecks, macro, tech, etc. I like warm water.
So, you're probably not looking for the best diving period, but for a compromise that combines diving, infrastructure, paying diving jobs unless your special one is all remote, and perhaps a few other things you'll need to list.
How sure are you about moving permanently? One of the best things about the dive instructor lifestyle is the mobility. It's also one of the worst things about it: you'll eventually miss the perks of owning things other than your gear, remodeling your home, or having a family, and settle down. But it's just that much better to have a decade of teaching around the world to remember and tell stories about, rather than just your old urban life.