mxHero Toolbox
adds some features missing from Gmail:
  • Tracking (read receipts that always work, plus tracking of clicks on links in the email)
  • Send Later - schedule delivery for the future minutes, hours, or days ahead
  • Private Delivery - every person addressed in the To: field will see just one recipient address - his own
  • Reply Timeout - remind yourself to follow up if you don't get a reply
  • Reminder - remind yourself to deal later with a message you received from anyone else