Hi,
I have a query set up right now to accept a user's input for a specific field on a report, and i'd like that inputbox to default to a certain text string based on an expression. Right now it always shows up as blank.

Can i do this??

Only by using values taken from a form or using VBA to create a dialog box.
It is much better to use a form for input than the default parameter dialog.
The form holds the values until cleared so the user doesn't have to enter them every time.

Set the Default value of the textbox control on the form.

Refer to the value of the control in the query as:
Forms!formname.controlname