Congrats and welcome to BDW! As everyone else has said, you will definitely find a ton of information and ideas on this site, and everyone is more than willing to share!
You don't say if you're in the US or canada, although I suspect if you're considering Cuba that it's canada. Americans still are not allowed to travel to Cuba from the US, although I've heard they can travel there as long as they arrive from a country other than the US. Having said that, depending on the province you might be in, there are any number of travel agents that you could get a recommendation from on this site, but a travel agent is definitely a must! A good one will make your life easier, and your guests as well!
As to where.... well that's much more of a personal choice, You need to think about what you want, where you've been and the type of wedding you're looking for. Each country that you've named offers something different and special. Absolutely reading the resort reviews will help. They're organized by country so you can be selective and read what you want to. that will go a long way to helping with a decision. The other, again, will be your travel agent! A good one again will help you with what each country/resort features in terms of what you want and it will be important to let them know what your "vision" is for your wedding, and let them help you with it!
Then work with this site, and you'll find pretty much everything else you need here! Past and present brides (and grooms) have given of themselves here so I'm sure you will find information on just about anything you can think of!!
Good luck and happy planning!!