With the advent of music by the download and Apple's iPod / iTunes franchise, more and more people spend more and more time listening to their music on their computers. This has given birth to the world of speakers especially designed to work with your computer.
The pioneering speaker system in this space, called the Elan, was released by Evett and Shaw, powered by an audiophile-looking amplifier called the Flatte 50. Built to incredible specifications, with custom Lexan side panels, these audiophile speakers sat on granite bases and used a di-polar speaker design.
XHi-Fi's XDC-1 is a more recent design that uses a ribbon tweeter to provide an audiophile sound from a thin, round speaker powered by a digital amp housed in a subwoofer designed to be placed below your desk.
Beware cheapie computer speakers that cost $100 or less, as they sound as good (or as bad) as you might expect.
Most computer speakers are active designs. With the better systems, low-rez MP3 audio will be painfully apperent, so you're better off finding some high-definition music downloads.
Other companies that make desktop and computer speakers are Polk, Klipsch, and Logitech.
HomeTheaterReview.com's desktop speaker system reviews include:
Xhifi XDC-1 desktop audio system
Logitech Z-2300 2.1 desktop speaker system
Boston Acoustics SoundWare loudspeakers
Aux Classic 2.1 desktop speaker system