Provide a complete history.
When auditing my account, I have to click several times to see the history of various MONTHs for various TYPEs of transactions. It would be much, MUCH better if I could access a single page that provided all transactions since my account was opened.
I realize that can eventually become quite cumbersome for an account that does a lot of transactions, but a simple solution to that is to charge for it. You could also add filters (time-span, transaction type, etc.) so customers could limit the amount of data they are requesting to only what they need.