I'm a big fan of Polk Audio's bookshelf and floor-standing speakers, so when it released two iPod speakers, I just had to check them out. Both are available in black or white.
The miDock Portfolio ($119) is a portable model and is compatible with any iPod via the supplied plastic adapters. It also has an auxiliary input for non-Apple players, though it'll only charge dock connector-equipped iPods. The speaker is pretty small and folds up flat for traveling. It has four 1-inch drivers and runs on four AA batteries or the included AC adapter. I took a quick listen, and it sounds pretty good for something so small, and would be good for hotel rooms and such. The included carrying case is cute too.
Polk is also taking a run at the Apple iPod Hi-Fi with its miDock Studio, which is fairly large but still portable, thanks to battery or AC operation. Its two 3.25-inch full-range drivers and ported enclosure give it a reasonably beefy sound, even on the noisy CES show floor. I dig the backward-slanted design, which keeps the sound pointed at your head if you've got the speaker placed on a low table or the ground, as well as the simple six-button IR remote. And at $229.95, it's cheaper than the iPod Hi-Fi. Sadly, there's no carrying case for this one.