Greg Laden likes YouTube clips, and some originating with David Attenborough really stand out. Take this first one listening to the Magnificent Lyre Bird, a second with raising Whooping Crane chicks, and a third displaying the Superb Bird Of Paradise.
Attenborough has produced over 150 hours of video of the highest caliber, covering so many different areas of nature. My favorites are Blue Planet, Planet Earth, The Life of Birds, and Life in the Undergrowth, and my wife and I own the first two to re-watch every now and then.
PS – How could I forget that it was Earth Day?