I've recently started using my MBP in clamshell mode with an external display, and the MBP's internal speakers aren't really optimal for that, so I'm looking for a pair of fairly cheap but decent external speakers. Sound bar and pill type speakers are welcome, too. Must not be a 2.1 configuration. The smaller the better. Preferably $30-$50 range, and certainly not above $60. Extra points for USB input rather than 3.5 mm, but that's not a requirement. I'm not very demanding when it comes to sound quality, but it must be tolerable. They're just for casual usage, and I won't be using them very much for music - I have headphones and a proper stereo for that. Suggestions welcome!