Adina quotes "Ducky's laws of e-mail", which comes from the discussion forums on Mitch Kapor's new Chandler PIM project. Rule #2 - People want to be able to see all their "to-do" messages -- ones that they need to read, respond to, or act upon -- easily. - boils down to: e-mail gets used as a surrogate for a todo list.
My biggest problem with that is for all of the things that I want to do quite independently from anyone in e-mail land prompting me to do them - should I send an e-mail to myself reminding myself of tasks to be done, and then do them that way? So puzzling to try to negotiate the combination of "things to remember to do on the way to town" vs. "projects that require computing to get done". Why not instead use the physical world around me - the piles of stuff around my desk, the look on my two-year-old's face, the color of the sky outside -- to drive the inevitable question of what to do next?