Take a look at the Sony Vaio VGP-USP1 USB Speaker, a four-watt (2x2W) enclosure that's 10 inches wide, and at a relatively heavy 18 ounces, it weighs enough to actually sound good. Sony didn't announce price or availability yet.
You'd be surprised how convenient it is to have a USB speaker lying around; it's especially handy for plugging into notebooks. This one reminds us of the JLab B-Flex, an excellent $40 speaker that's just right for a quick listen here and there.
Sony USB Vaio speaker [Akihabara News]