Date Pick-List Question

I have an accounts receivable report that has an "as of" date picker. Every time a user  opens the report the most recent date is the last one chosen. Does anyone know of a way for the default date to be the most current date? For example, if a user openned the report on May 29th and selected this date from the drop-down, then closed the report, and reopened it a day later, the 29th is the date selected. Ideally, I would like it to be the 30th. I thought about creating a derived table with the most current date -- Today() -- and then adding it to the data model, but I'm not sure that's optimal.

Thanks.