Auto electronic bill pay based on entered information.
1 to 3 month, and 6 month calendar based listing of upcoming bills based on data entered - also can be set to auto pay.
Account naming, ie "John's Personal" "Paypal Acct" etc.
Set it up graphically, so it could be read or interfaced with by mobile devices such as blackberry, iphone, or other via the bank's webiste.
Download account data to a generated excel spreadsheet file ("backup" whatever).
Set it up so you either beat the tar out of this program with a security stick first, or account for the fact you may want higher
or lower levels of security later / per client. Scalability in a word.
Also law of software development... get them to buy the really neat and useful core version... then get more out of them
by module upgrades which add some of these features.