I know it's a cliché, but yes, I plump for the Galapagos. But not because I have a special interest in fauna (and, frankly, still less flora) but simply because it is in so many respects like time-travelling to the very distant and dramatic past.
What greatly distinguished our last trip was a week in Ecuador beforehand, travelling from the high mountains, right down to the coastline. The first time I have ever ridden atop a mountain train - a true adventure indeed!
Do you know what the most vital piece of equipment you will take on your trip is? Forget the camera, forget the tech, forget the insect spray and everything in your backpack; it’s your feet that I am thinking of.
You don't need to be especially fit for most adventures (thank goodness, from my perspective), but most trips will involve, if you are to get the most out of them, an awful lot of walking on varied terrain.
So, please, look after your feet and make sure you bring the very best, and the most suitable, footwear that you can (and that it's fully 'broken in' before you travel).