Logitech's Z-2300 speakers were a great set of computer speakers: THX certified and not atrociously priced. The upcoming Z623 speakers seem like a pretty good successor to the aging system, complete with an updated look.
The Z623 will be $150 in September, and have RCA as well as 3.5mm inputs, so you can connect it to a computer, PMP or your (albeit low-end) home theater. These speakers, unlike the Z-2300, have volume controls on the satellites rather than in a separate control pod. I've actually run into problems with the Z-2300 control pod wearing out after a few years of use, turning a 2.1 system into a 1.1 (or 1.0) system where only the left channel works. [Logitech]