Within my main inbox I have 3 sub folers: Do, Done, Defer and 3 macros to move the selected folder into the relevent folder. (alt-1 moves the selected mail to done and then selects the next mail). Each day I quickly filter my inbox into the three folders. I can process several hundred mails in 20 mins or so.
Do, something I expect to process today. Done, something I don’t care about/have read and understood, I dont expect to refer back to these today. Defer, something I will do something about but not today.
At the end of processing I expect my inbox to be empty.
At the end of the day all mail items in Do move to Defer (I dont want to keep things in Done overnight).
At the start of the day all items in Defer are filtered using the rules above, I dont want to leave things in Defer for more then a day or 2. If stuff hangs around for too long I will add it to my diary to process later.
At the end of the day all mail in Done is copied into an archive folder based on the month/year. Done is just a parking place for things to be archived.
I use a tool to index my archive, I actually use X1 but google desktop is an excellent alternative.
I filter out any important facts i would like to refer back to in outlook notes.
I filter out any tasks I would like to recal into omni focus (http://www.omnigroup.com/applications/omnifocus/) the best GTD I have found.
I DO NOT EVER use my inbox as a todo list or a mechanism for recording subtle facts I want to recall later. I know a lot of people do but IMHO its just a bad way to be.