
With all things being equal, digital input speakers usually beat analog for the simple fact that you don't need a high end sound card to take full advantage of them. After all, digital is digital and spending big bucks for a soundcard is just wasted money. Thus the money you would spend on a "audiophile" grade soundcard can be put towards the speakers. Unfortunately, not all that many desktop speakers actually use a digital connection. Even more rare is a set of speakers which not only don't use the typical 3.5mm or 6.3mm stereo jack connector but also don't use a TOSLINK or SPDIF interface and rather use the ubiquitous USB interface.
This really does seem counter-intuitive as
digital is digital and how the 0' and 1's get to the speakers doesn't really matter. One such set of speakers which not only are digital but also use a USB interface is the Palo Alto Audio Design Cubik digital stereo speakers. On the surface these funky, 5.4" cube shaped speakers with built in stands don't seem to warrant an asking price of basically $200; however, these bad boy not only are
small and sexy looking but have pretty good performance specs to back its asking price. Also to be blunt when compared against similar performing speakers such as the
B&W MM-1's (which go for nearly $500. ), the Palo Alto Audio Design Cubik speakers are actually pretty reasonable. While not for everyone, it - pardon the pun - sounds like you could do a heck of a lot worse than these bad boys.

Creative ZiiSound T6 Speakers Offer Both USB Virtual 5.1 Surround & Bluetooth Audio
By Ian Chiu on April 1st, 2011