Getting Things Done on a Macintosh | Ask MetaFilter

Looks like a good thread in the green to watch and maybe contribute to.

Having recently finished Getting Things Done (and after following 43 Folders for some time), I’m inspired to organize my life. I’ve gathered supplies and plan to organize my physical life this weekend. My on-line life (based on a Mac) needs help, though. How do you stay organized on your Mac? Do you use iCal? (It still seems so buggy to me.) What e-mail program do you use? Is Microsoft’s Entourage all that? I know about Quicksilver, but can you recommend other little apps to keep my digital life organized and worry free? (Tips on physical GTD organization are welcome, too.)