I'd of said without question the Great Barrier Reef down under. Few places on earth offer a diving experience that comes anywhere close, though you will have plenty of company as thousands travel to Australia every year to feast on the breathtaking underwater scenery.

There are also plenty of spots in the Caribbean, though no one place springs to mind.

Yes I would have to agree the Great Barrier Reef would be spectacular. I also hear the Red Sea is also another great spot. Sharm El Sheik and nearby spots. I would have done my PADI either at Great Barrier Reef or Sharm El Sheik.

I could imagine that the Caribbean would also have some fabulous spots.

World Traveller and Chocolate Eater :)

Great Barrier Reef is an all time recommend from anyone that has dove, or still wants the chance (the latter would be me). Some places off of the the Florida coast line are nice as well some in Hawaii. I would check your budget to see what is close (and cheap) before you fly 1/2 way around the world first! Oz for me, is still yet a dream within a dream. :)