If you want to stream audio output to multiple speakers from your Mac, PC, iOS or Android device, I can tell you that this DIY article is spot on. Based on that article I just did a very similar thing, with good results. The only caveat is that the volume knob on the Lepai LP-2020A+ is very tight, and only seems to work in certain positions, but other than that, the approach works as advertised. I went with the Micca MB42 Bookshelf Speakers for $59, but in retrospect I wish I had tried the smaller Micca COVO-S Compact 2-Way Bookshelf Speakers.
I haven’t tried their software yet, but a friend of a friend recommends Boom, which is a “system wide volume booster and equalizer application that effortlessly improves the sound of your Mac.” Boom is actually a software application, not a hardware product.
I don't write about products or services too often, but I really like the idea of the Logitech Speaker Lapdesk N700, pictured here:
I don't own a tv any more, but from time to time I'll watch some videos before going to bed (either shows on Hulu, or something from my DVD collection), and this "Speaker Lapdesk" looks perfect for that occasion.
I've had an Altec Lansing inMotion iM600 speaker system for almost half a year now, and I'm very pleased with it. It supports older iPods, like the iPod Nano I used to have; the sound quality is very good; and I love that it can run on either AC power (i.e., plugged into an electrical wall socket) or you can disconnect it and run it off the battery for a very long time -- it hasn't died on me yet during normal use.
My Altec Lansing inMotion iM600 product review has been moved here.
Whenever I plug my iPhone 3G into accessories that I used previously with my old iPod -- including an Altec Lansing iM600 external speaker system and a JVC car stereo -- I get the scary message "This accessory is not made to work with iPhone" (followed by a message about switching to airplane mode). That message is almost mind-blowing scary like "Your iPhone is going to be fried if you stay plugged in to this device". Is it really that bad?