I primarily work in an office environment. Used GTD for about 12 months.

For email- I get about 100 per day. Currently have only 5 unprocessed ( 6 months ago it was more several hundred!!)

At work its all about Entourage which i set up according to the $10 guide sold on the GTD website and set it up for integration with a Palm. Used to use Outlook and its about the same.

Biggest trick i use now-Use the "create tasks" or "create events" from emails shortcuts (also in Outlook) so that actions have the text of the email as an attached note.

As for dealing with email: I have 5 folders for email
@action- longer than 2 minute actions emails
@action-support ( emails get moved here when they have been either been acted on and need to be kept or I have processed the emial so I know what the next action is)
@waiting for (emails that Im waiting for a response on or that had an action I did separate from email that Im waiting on)
@ someday (emails that have no immediate action but might at some point)
@reference ( reference emails that I wnat to kepe but have nt action associated with them at all)

periodically I archive these off to a separate server to identically names folders

For other things it really is just a case of using the tricks outlined in the book, all the time, and strictly adhering to the do, delegate or defer ( for all inputs), making notes and putting them into the inbox or direct input to palm when on the go, but a notepad would work fine. Indeed thats what I use in the car when I need to jot something doen while stuck at a light.

In a meeting be sure to use the @ sign to highlight things for post review.

For voice mails i immediately make notes in Entourage while listening as an @call task.

When Im chatting with someone in my office I always make notes and the sheet go in the inbox. ( had numerosu occiasion where soemone has come back to me weeks later and said" hey remember when we were chatting about x what did we say" and lo and behold I have the notes!

For emails that contain things that need to be read, print them immediately or lat least downlaod all support material and a text copy of the associated email into folders names for the project. Its amazing how in the past i had the file but spent a lot of time tracking down the email, so now I store a text version or print it with the printout.

The label maker and a-z filing system is liberating and really works.

I switched the type of paper pad I used from a legal "flip over" pad to a simple letter lined pad so that I can write and tear off easily and put the sheets in folders/inbox. A small change but really works much better.

Date everything.
Embrace the Inbox as the place for anything and everything that is unfinished and/or may have an uncaptured action associated with it.
And be religious about the weekly review for actions/projects, and quartely reviews for higher levels.

And be sure to have an inbox at home also