I got the BBC series Planet Earth as a birthday/Christmas gift too. We have spent many hours since then watching all it has to offer.
The technology used, combined with the dedication of the film crew, and the budget available puts this series at the top. The shots are pure eye-candy and the commentary can be eye-opening.
One of the first ones we watched about caves featured a part of New Mexico that I never knew existed and I wasn't alone in my ignorance until recently. I was blown away when I saw the footage of La Lechugilla Cave that is part of the cave system in Carlsbad, NM. The cave was completely unexplored until 1986.
You can read more about it and see more amazing pictures at wikipedia.org