Here is my system of not wasting too much time on e-mail: I only have one client application set up to access my various accounts - Zimbra Desktop, which I don't have any entries for in the OS menu, and I don't know any passwords myself as they are randomly generated and stored in KeyPassX.

Every day a cronjob starts up the client at 4pm, which starts minimized (thank you, KDE), proceeds to fetch new mail, apply various filters (e.g. CCs marked read and archived), and maximizes the window 2 minutes later.

Half an hour later another cronjob does a 'killall' on it - that way if I wasn't at my desk at 4, I wouldn't have to come back to be greeted by unanswered e-mails.

And, as the article says, there is always a mobile phone for anything truly urgent.