Tips for better use of email

Steve has a great list here. Some include:

1. Check email sparingly. Three times a day, max.
5. Keep email replies short.
6. Automate the repetitive. Use a program like TextExpand to speed up typing regular phrases.
8. When you are replying to emails, just do that, not several other things.

What do you think of his list? What tips do you have?