Depending on the amt of mail you receive I have 2 strategies that can be used together:
1) As most people suggest above, use your inbox as your todo list, and keep it clean. have 1 folder for Archived mails, and use all the search tools for searching!
2) If you get HUGE amts of mail, then use a filter to move mails that you are only CC'ed on to another folder. Then only check that folder N times a day ( I used N=3, morning, lunch & home time )
You will be amazed how much time it saves you, esp if you find that you feel drawn to reading mails that are in your Inbox trying to keep you Inbox clean.
This stop non-urgent mails from disrupting your flow, and is just quicker because you can now read the entire thread of the conversion by the people who were in the TO list.
HTH
