I guess I'll be repeating a bit of the stuff already said, but, for me, it'd be important to have:
- Name of Loaner
- Loan Date
- for me a return date is not important but it's likely that for some other persons it is.
- Possibility of printing/displaying a report with "on-loan" CD's list showing date and loaner

For me, that'd be it.

Cheers,