Ed Eubanks is one of a handful of writers who tackles the very interesting but challenging intersection of personal information management, calendaring, task and project management and "getting things done".
His most recent column for About This Particular Macintosh outlines his plans for 2009: ATPM 15.01 - Next Actions: Article Line-up and updates his long, long lists of OS X "next action" apps. His complete archive is here.
Tidbits, and especially Matt Neuberg, cover the same domain -- such as Adam's latest column on Notebook 3.0. Matt's more or less moved on to work on FaceSpan, but you can read his past columns here or via a search on Tidbits.
I'm glad Eubanks is still working this domain. The killer problem for all these apps is proprietary file formats and data lock, I'm going to ask Ed to focus more on those topics.