I vote - as always - for the Cambridge SoundWorks "Soundworks" powered 2.1 system. Its almost 10 years old, but IMO it is still quality bang-for-the-buck.
Most mass market 2.1 computer speakers overemphasize treble or bass to "woo" purchasers. But, you quickly realize that the speakers are crap after listening to its boomy and harsh sound for a few days. The Soundworks, on the other hand, was designed by the late audio hall of fame inductee, Mr. Henry Kloss, and the tonal balance on the Soundworks is very good. On absolute terms, compared to Hi-Fi speakers the Soundworks might sound touch thin, but that's more of the price and thus drivers limitation rather than a design flaw. I've listened to other 2.1 models like the logitech, KLH, Advent, etc., at stores but was never as impressed with them as the Soundworks.
You can purchase the CSW "Soundwork" for $70 from hifi.com.