Forgive me if this has already been suggested or there's already a way of doing it, but the one thing I would love to see in Checkbook would be a customizable button (or two or three) that simply enters a user-defined entry when pressed.
For example, since my bank doesn't charge ATM fees, I'm always stopping off on the way to work and getting $20 from the machine. In the past month and a half, I've had about 20 entries in my checkbook marked "ATM Withdrawal". It would be fantastic if there were a button at the top of the window that I could click and Checkbook would automatically insert a $20 ATM withdrawal entry with today's date, customized via a preferences window that would allow me to set the information that's entered from that button. Basically a shortcut for common entries. I click the button and a $20 ATM withdrawal is automatically added with no user intervention.
But even if that doesn't make it into future releases, I'm still happy with Checkbook the way it is...
