One feature I am thinking of adding is a way to keep track of how long the fans are on. This will allow me to see how well it is working, and get an idea of what kind of weather it takes to get heat out of the attic. Ideally, this would be from an LCD, but I don't know how to program one yet.
Perhaps for now, I'll just keep the laptop connected to it for the first couple days and it can log the on time directly with the serial connection.