Best Small Office Speakers

I'm looking for a pair of very small speakers (max 12" high) to go with my NAD L-40 CD/Receiver for my office in a bookcase. I listen mostly at very low volume at work, and the NAD is only 20 watts per. Any suggestions for a good, reasonably priced (used?) pair? Maybe a great deal on a pair of used Tukans, or some PSB alpha minis? Thanks for the help.