Change the frequency with which your email client checks the server.
Most email clients such as Entourage, Eudora, Mail, etc, have a setting for how often the program checks for email on the mail server.
Since email is a major distractor, it behoves you to adjust the check email frequency from once every 5-minutes to once every 20-30 minutes.
Any quicker turn-around should be handled with the phone or IM.
In my office, we use Exchange as our back end so our email is real-time, but when I was running a POP3 client, this change would have saved a lot of time for me.
Thanks to ProBlogger for the tip.
