Don't use MSN, that's a good start.

My computer checks my mail for me every 5 minutes. I like having some kind of little applet running nonstop that displays how many new emails you have. Opening a mail program just to check if there's any need to run the mail program is a waste of precious seconds. I don't like popup alerts, because I'd probably miss them, and I get spam approximately 20 times more frequently than real email.