DeepDiscount.com has the BBC Video Planet Earth: Complete Collection on DVD for $54 - 20% with coupon code DDAF [Exp 11/25] = $43 with free shipping. This release includes all the episodes (5 DVDs) from the original BBC production, as well as an extra 90 minutes of footage not seen in the original show. Narrated by David Attenborough rather than Mrs. Alien (in the US version). The HD-DVD and Blu-Ray versions are $53 after coupon.
I just bought the Blu-Ray version for $53. Smoking deal for the entire series!