All of this advice is usefull...however...
The most important thing to bring with you is common sense and good judgement!!!!
There are still pirates in Belize, they just don't have wooden ships and steel cannons anymore.
I know of a couple that came down loaded with $$$, had a great plan and jumped in with both feet. They wouldn't listen to advice from certain people, thought they knew the best way to do things and figured it was just like the states. They put all of their faith with the wrong person and didn't protect themselves financialy. They are now back home licking their wounds and getting the thorns out of their paws.
Many of you reading this have heard the same old story over and over again.
That being said, I have had nothing but wonderful experiences and look forward to being an island resident some day. There are many folks on the island that are the finest people I have ever met.
Enjoy your adventure!