Re: time shares
Think about it for a few days before buying it.
I have enjoyed mine - staying at the condo in Park City when skiing every day is nicer than driving home and back every day, even with my home only a 30-45 min drive away. I've also traded for time in other places, but remember that you have to pay the maintenance fees regardless of use, and if you use it there are extra cleaning fees. Get a true list of all the fees and such, as they never tell you about them up front.
If you really think you'll use it every year whether in the keys or elsewhere, it MAY be worth your while.
However, like NavSport said, it is sometimes less expensive to vacation through other means.
In fact, you can usually find a one time rental for the same place on the internet for less.