Rio Carbon. 5gb.
Pros:
1) Great battery life, 20+ hours, just as advertised.
2) Cheap. I paid 140 shipped.
3) Plenty of storage for my needs.
4) Good sound quality.
5) Has a voice recorder, and the microphone works well.
6) Small, cool lighting on it for use in the dark.
7) uses a standard mini usb jack for charging/synching. You can pick up a $7 blackberry charger for use in the car if you need one, so no need for any special adapters or whatnot. Makes life easy.
8) USB 2.0 speeds. which is nice.
9) Doubles as a 5gb usb drive if you don't mind carrying the cord in your backpack.
Cons.
1)The little scroll wheel doubles as a button, which is a cool idea, but the mechanism is fragile. Drop it once and call it done. But...super glue is your savior if you want to pop off the case and fix it yourself as I have done. It hasn't broke since.
2)No on-the-fly playlists/queing of tracks, at least on the version of firmware I have on the player. Rio might have listened to the pleas of carbon users around the world and added it in more current firmware, but I haven't taken the time to check for updates, as it isn't terribly bad for me. Selecting a new album to play after one is finished is pretty painless.
3)Chrome/Polished backplate gets really grubby, similar to ipod backings. I don't really care too much.
4) The player doesn't have a real accurate clock, and it likes to reset it's clock if the battery gets too low.
5) The phonejack isn't grounded very well, and for some headphones, you get static noise. Just buy some plugs that are insulated around the jack, so that the jack doesn't ground out on the player.
Other than those things, It's an awesome player. I've been using it for about a year now, with no complaints, and there is no noticeable battery life loss. It's cheaper than an ipod nano, not as bling, but it gets the job done. The battery life is amazing. I've been in the lab, and listened to the player using my Koss ar-20 studio sized headphones for 20 solid music playing hours before having to put it on the charger. Great player for the money.