I'm ridiculously attached to my stacking trays, the way other GTDers are attached to their Hipster PDAs or favorite computer apps. Trays work well for people who do a lot of thinking with paper (often a.k.a. "pile people").

At the periphery of my desk area here at work, I have two hanging "pockets"--one is in, the other out. I like having an Inbox at the edge of my work area (even though it is out of arm's reach) so that people can drop things off for me without interrupting me. I use the Out box there to keep outgoing things off and away from my workspace.

Then on my desk, I have four stacking trays. From top to bottom: Inbox, Needs Action, To Sort/File, and Read/Review.

I put things in my own inbox all the time. Someone calls and I jot down a message, but I'm in the middle of something else--message goes into in. It's the end of the day and I have six papers scattered across my desk--they go into in, for processing in the morning. I get out of a meeting--the agenda and my meeting notes go into in, so that I can at least check my e-mail and voicemail before processing those notes. I find it extremely useful to have an inbox right within arm's reach.

The "Needs Action" tray is for paper items which serve as their own task reminders. Right now I have some meeting notes in there--I need to type them into minutes. Maybe someone has given me a paper I need to take care of--goes from "in" into "Needs Action." Or perhaps it's a brochure for an event I want to attend--that goes into "Needs Action" as a trigger to actually register.

The "Sort/File" tray is a favorite. I am often not in the mood to file something away, but I know it needs to get filed. I just stick it in "sort/file" and then I can take care of a stack of papers all in one sweep later on. I have learned to include in my weekly review the task of getting this sort/file tray to zero. Otherwise important items can get lost in there.

Then at the bottom is the "read/review" tray. It's gotta be at the bottom because it gets the heaviest, with magazines and newsletters and long print-outs.

To top it all off (literally), I use a Rubbermaid Sort-a-File Center. I use the first two slots as specific outboxes (one for each of my two bosses). I use the third slot to hold my "waiting for" file folder (over time I have come to prefer a folder rather than a tray for "waiting for", since the papers are all different sizes). The fourth and fifth slots simply hold short of 100 blank manila folders. When fresh folders and my labelmaker are right at hand, I resist filing items less than I would if it was an ordeal to create a new file.

At home, where I do some creative writing, I sometimes employ a "works in progress" tray, where writings sit while I'm drafting them or between revisions.

I've been doing GTD for four years now, and these are the "buckets" I have found to be useful as trays. It's worth noting that in addition to the "Needs Action" tray I keep paper "Next Action" lists, and I use a "@Action" e-mail folder.