Planet Earth - The Complete Collection (Blu-ray Disc, 2007, 4-Disc Set)

I own both the BBC and Discovery versions, and they are both a feast for the eyes. Be wary, as the runtime, narration, and resolution for the different editions are EXTREMELY dissimilar!!

Be VERY careful, as just about EVERY version you find on ebay (and shipping within the USA) will most likely be the shorter running Discovery Edition, which mostly has a monopoly on the US market. If you want the BBC version, you typically have to purchase online through a british vendor (ie Amazon.uk). The BBC version is well worth an investment (if you must choose between the two), especially since you can usually procure it for about $35-$40 USD when the dollar is strong against the pound.

Concerning 1080i vs 1080p:
Both state on the box that they are 1080i capable--this is not entirely true. The BBC version is mostly in 1080p, while some extras and bonus content are encoded in 1080i. For the Discovery version however, the entirety of the videos are in 1080i due to poor encoding.

David Attenborough BBC Edition:
Most people prefer his narration because he put a lot more heart into it. However, some find this edition annoying because he talks more than Sigourney in the US version. NOTE that this version has an extra 10 minutes added to EVERY episode when compared with the truncated US version as seen below. This features an extra bonus disc that isn't available with the Discovery version---so this includes 5 discs total, and 2 bonus episodes.

Sigourney Weaver Discovery Edition
While most people are disappointed with her narrating style (not as much "acting" and emotion in it), most will agree that this is not a BAD version. The intros to each episode are more beautiful than the generic version for the BBC edition, but each episode is missing an extra 10 minutes due to US programming/commercial issues. This version does NOT feature any bonus content (as in the dvd and BBC blu-ray versions). There are 4 discs total, and is overall the weakest investment of the Planet Earth Collections.