No list of excellent cruising blogs would be complete without Mahina Expeditions. Their web site is, of course, primarily devoted to their commercial endeavors – books, seminars, and cruising expeditions. However, you can learn a great deal about 'round the world cruising by perusing both the current expedition travel log as well as entries from past trips.
A bit of a disclaimer on this one. I owe Amanda a great deal. She has been both a source of great motivation (e.g. repeatedly kicking me in the pants) as well as important introductions which have provided me with an entree into the sail magazine publishing world. Nevertheless, I read her log because I enjoy it... though you can pretty much write me off these Nordic destinations after reading about their most recent trip.