I thought Blue Planet was good, but it was done a decade ago, and it clearly doesn't have the same production values. Wild Russia was pretty good, some visually striking imagery, but it's got a narrow focus (as the name implies). Galapagos was a short three-part series that is worth watching; a little too much focus on how man's history has interacted with the islands, but the photography is very good and the flora/fauna are beautiful (but I'm biased, having been there and whatnot).