Windows Phone Thoughts: Portable speakers for traveling?

Ok, we've had some terrific advice on headphones and earbuds which is great for travel. I've been using the Sony MDR-EX70LPs since March of this year, but what about portable external speakers? I often want to take my iPAQ to a cabin or hotel room and listen to music or an audio book without the tinny sound of the built in speaker or the hassle of walking around the room or even sitting at a desk with earbuds in.



I've been looking at the Sonic Impact SI-5 Flat Panel Portable Speakers (affiliate link) and they look pretty good. The only downside I see is they seem to require 4 AA batteries. I would prefer the option of an AC adapter. Does anyone have these? How do they sound? Any other recommendations for portable audio for Pocket PC fans?