I'm pretty happy with my SI-5 portable speakers $15-20 at target when I bought them. They are a bit larger than a double CD case, and are kind of off to set up (uses two cables, one for left to right speaker, and one for input), but the sound quality is reasonable, has no sweet spot whatsoever (one of the "benefits" of NXT flat panels), and gets prety loud for being a $20 or less speaker that runs off 4 AAAs.
It's not super sound quality though. If you want better sound quality, then look at the creative Travelsound, and find a way to set it above your laptop's display.