Logitech X-230 PC multimedia speaker system - £23.99 or less delivered @ Amazon !
Posted by Ray earlier; this has slightly dropped in price + there is now the option of getting additional £10 discount for signing up to Amazon DVD rental or £15 for Amazon / Halifax credit card.
Description : Crank up the audio on your PC with this 2.1 speaker system and enjoy clean, crisp, consistent sound from your games, music, and more. The Logitech X-230's high-tech subwoofer adjusts itself dynamically to deliver distortion-free bass. And the two wall-mountable satellite speakers use Logitech's patented FDD2 technology to eliminate the uneven sound response created by conventional dual-driver designs. The result: a clear, uniform sound field without the "hot spots" and inconsistency of other dual-driver satellites.