The clearest stereo multimedia speakers under $100 are basically:
1) $99 Klipsch 2.0 Ultra
2) $75 Altec Lansing MX5020
My room mate has the Ultra, which is really amazing, they compare to my Axiom M22tis ($440) really well in the bass area, and not only get loud, but have far better clarity, dynamics, and decay times than the Klipsch 2.1 Promedia we had.
As for the MX5020s, they are very impressive as well, although definitely not as clear as the Klipschs (a lot more distortion on the low end; then again it's something all Altec Lansing speakers have suffered since they moved into the "flat panel" speaker designs). However, it's still very impressive, especially considering it's a 1" tweeter and 3" midrange against tweeter and dual 2.5s for the 2.0 Ultra.
Both of these speakers are HUGE for multimedia speakers, with the Ultra having the advantage of a very deep 6.5in cabinet (compared to a very thin but tall and wide one for the 5020s). This is probably what translates to the less distortion in the bass response, and less reverberation in the cabinents.
Both of these...make my old Logitechs (Z-680s) sound way out of its league. All I can say is, the budget 2.0 market is becoming VERY impressive with these nice speakers by Klipsch and Altec Lansing.
They aren't as impressive looking as all the "toy" multimedia speakers out there, and are built for sound quality. I would suggest them for music, but of course the toy speakers have their market too for the kids who like all the flashing lights and nice silver designs.