You can now set up an automatic report based on donation range that will trigger a notification email with a list of the donors within a certain range.
For example, the Executive Director of a charity might want to see a weekly email with a list of all the donors between $250 and $1,000. And a separate email for anyone over $1,000 so that she can send them an personal thank you. Another example might be the email is triggered to a person responsible for sending out special Thank You Gifts to different levels of donors.
The setup is under Donation -> Setup -> Donation Summary Email Setup: