I just went through about 4 players in a row. I started off with a Shuffle, liked it for the size and the none cord connection. However to me the shuffle sounds very flat. Not being able to adjust sounds via EQ is a breaker for me. Then went with a Samsung YP-U2 1GB, great little device, sounds great...9 band EQ and 3d sound makes it a much better choice over the shuffle just for sound quality alone. Also, the samsung is a MTP device...however you can flash it to a euro firmware and make it a UMS device. After playing with it for a while, i decided the screen is too plain and wanted something with alittle more space, so I returned it and got the 2GB Samsung (same YP-U2). Again, after playing with it for a day, i decided that i needed a better screen. The Samsung screen is nice, alot better than the no screen from the shuffle. It was just to small at times. Hard to read.
So now im using a Zen V plus i just got from BB, 2gb model. Ive only had it a day but its a great DAP. Sounds great, 8 EQ presets, 1 custom (5 band EQ). Screen is nice and clear...easy to use. The joystick is alittle small, but its easy to use. Transferring music is easy...also can set a certain amount of space on your player to show up as a removable drive (with drive letter). This makes it easy to grab stuff from another PC (in my case, swapping music with my friends.) The nano sounds very much like the Zen, at least my buds older 1GB Nano sounds pretty much the same.
I havent tried out the very very new shuffle. Its soo tiny in person you will probaly laugh when you see it. I heard it pretty much sounds the same as the first shuffle, flat.
This is my personal opinion, you will find that people out there think they shuffle sound as good as others, i dont find this to be true. I belive that the lack of custom EQ settings makes a huge difference.