Especially for large research projects with many possible sources, add a new output format:
When collecting possible research sources into a bibilography for sorting/searching, I exported to text.
After export, I found I needed to spend a good deal of time editing the text file to put it into a form suitable for import into a spreadsheet so that I could sort on author, title, call number, etc, from offline.
So far, none of the export options are easily converted into a form suitable for spreadsheets.

SUGGESTION:
It would be nice to also include an output option that exports catalog data into a form suitable for import into a spreadsheet, such as comma-separated or tab-delimited.
Even better, direct export into a spreadsheet format such as MS Excel (XLS).