UCube by UltraLink
Click here to buy it now at Apple, $150
These speakers are diminutive, sure, but you don't want speakers taking up too much desk real estate, do you? Of course not. The good thing about the UCubes, despite being as loud as they are small (each speaker can pump out 15 watts of power), is that all they need to work is a USB port. Both sound and power are delivered through one port, making them easy to disconnect and rearrange. That's probably why Amtrak is planning on bringing these to its quiet cars.