South Florida / Florida Keys Advice Needed

[ShadMan]

I'm heading down to Key Largo for about a week next month and am trying to decide where to go for the last two days we're there. I'm attending my cousin's wedding in Key Largo, so we'll be staying there the first four nights, but we are going to spend two more nights somewhere before heading home.

I'd appreciate any input from those who have been to the Keys. Our choices are:

Stay in Key Largo
Key West
Duck Cay
Islamorada
Miami (South Beach)
Ft. Lauderdale

It'll be just my wife and I. We're not looking to fish those last two days...just mainly relax and see what we can see.