I recently added 43 Folders to my blogroll and it's rapidly becoming one of my favourites.
It's a blog about "life hacks" from an OS-X-using fan of David Allen's Getting Things Done.
As longer-time readers of this blog know, I'm a big fan of the GTD approach to personal productivity too. I also recently bought a PowerBook (although I haven't ruled out getting a Tablet PC — take note Scoble!)