Just purchased one of these.

First thing I did was plug it in to charge, and flash the firmware.  Easy to use, painless.
Very nice UI - clean, intuitive (never had to touch that manual).  Got exactly what I wanted.

I'm still walking around with a 256 MB USB key for my work - and this product made me replace it.
At $120 CDN for 1 GB, compared to $70 for a just a 1 GB key, I'm sold.  Given the price of just the memory, the premium I'm paying for the 'player' functionality is minimal, and it delivers a wealth of features!

Excellent sound quality, clean and fast.  (USB 2.0).
I had feared that the little swing out USB port would be sketchy - not the case.  Well built, solid.
I had feared the UI would be hard to use - but Samsung has pulled it off.  They make great LCDs, and this player is no exception.  I got the songs I wanted quickly.  The way I figure it is: The battery life will diminish with use - worst case scenario: you're still stuck with a very nice USB key!

I'd definitely recommend this, unless you feel you need to walk around with more than 1 GB of music.  No moving parts in this one - which has always been one of my biggest concerns with these players.  This is well built, and solid.  Does voice recording too.  Comes with a pair of headphones.

Installs without drivers on Windows XP - shows up as removable disk.  You can drag on your own files into folders.
On player, you tag songs into a playlist, or just play the whole folder.  Full ID3 support.

If you currently don't have a player, I'd get this one.  Feature set is good, and it doesn't require you to install any software.  Just drag over files and you're done.  End of story.

No Apple markup.  No Apple bloat, no DRM.  I move files over MY way, and organize stuff my way.  No flimsy Apple products for me.

Details
Model code: YP-U1ZW/XAC
1GB built-in flash memory
OGG(up to Q9)/MP3/WMA/WMV
WMA DRM
White LED-4Line(128x64)
SRS WOW Optimization
Voice Recording (built in Mic)
USB Direct connection to PC
Headphones included
Playback Time: 13Hrs (Li-poly), PC charge
WXHXD (mm): 23.8 x 87.8 x 13.5 
Weight: 30g

Product Homepage: http://www.samsung.com/ca/products/digitalaudioproducts/digitalmediaplayer/yp_u1zwxac.asp

Quick Guide: (more images - click on "Location of Controls")
http://downloadcenter.samsung.com/content/EM/200508/20050810163653046/EN/main.html

Manual: http://org.downloadcenter.samsung.com/downloadfile/ContentsFile.aspx?CDSite=CA&CttFileID=642108&CDCttType=UM&ModelType=N&ModelName=YP-U1Z&VPath=UM/200509/20050917093240687_YPU1-CANADA-ENGLISH0.0.pdf