No Email
One thing I would really love in an email client is a strong separation between reading and writing email. During productive hours when I'm sitting at my desk, I would really like to be able to 1) open GMail, 2) read old email 3) Write new email.I absolutely do not want the ability to read new email during that time. In fact, I would really like to set up GMail so email only arrives on a fixed schedule, say 2-4 times a day.