Use Boomerang for Gmail to schedule email reminders right from your inbox.
The most important new gmail feature in years isn't coming from Google.
You can prevent important emails from getting lost in your inbox by using Boomerang to remove them from your inbox until you actually need them. At the time you specify, we'll bring it back to your inbox marked as unread, starred, or even at the top of your message list.
To make sure you don’t forget why you needed it in the first place, you can now attach a note to the message as you schedule it with Boomerang. When the message returns to your inbox at the time you specify, we’ll append your note to the thread.