This morning I stopped by CompUSA and bought an Archos Jukebox Studio 20GB MP3 player. I've been craving an MP3 player for my car, but since the discontinuation of Rio's car MP3 stereo, I haven't been sure which way to go. In the end, I decided that a portable player (and a cassette adaptor for the car) made the most sense.
The Archos player is a 20GB USB drive, which makes it one of the first portables that's big enough to hold my entire music collection. The thing that sold me on it, though, is that the controller chipset works in Linux as of kernel 2.4.8. Just plug the drive into your USB port, mount /dev/sda1, and go nuts. No crappy custom software--it's just an external drive!
The interface on the unit is dirt simple: you navigate the filesystem with four buttons, and hit play when you get to the desired song. Only one filename is shown at a time, and you can't skip past several at a time, which makes large linear searches a pain. Luckily, the player understands .m3u files, so you can populate the drive with pre-made playlists as you see fit.
The player contains rechargable NiMH batteries, and claims between 7 and 10 hours of continuous play, though I haven't confirmed that myself. Physically, the device is a bit big for "pocket sized", but it comes with a belt-friendly carrying case to compensate.
I'm not sure if the player supports USB 2.0, but since none of my machines are bleeding edge, I'm stuck with the really slow transfer speeds of USB 1.0. It's taking all day for my 12GB music collection to transfer.
Other than the slowness of USB, my only complaint so far is the filesystem's apparent hard-coded file permisssions. Everything is writable only by the owner, and the owner is root, which means you have to be root to write to the device. Maybe mount can do some uid remapping magic. I should look into that.
All in all, I'm impressed. I shoud make frivolous gadget purchases more often.