Very Small Desktop Speakers

Can anyone give me advice on small to very small speakers that could sit on a desktop? I have moved to a new open office situation where I have walls but no ceiling so my old Plinius 8200 and B&W 805 speakers are just too instrusive to some the others around me. My source would be my Apple powerbook or maybe a small CD player. Let's face it, sound quality is not the most important issue but size is. I was thinking of a Sophia "Baby" amp or something equivalently small--so speaker efficiency is also a consideration.
thanks for the tips in advance.