n3ON is my favourite Winamp skin. I've used it for several years, and I'm not getting bored with it. I still feel it's attractive and even beautiful.
When I tried to use it with Audacious 3.1.2 in Linux, I got a white box to the left of the time display and visualization area. This is because n3ON does not provide an image for when the Clutterbar is hidden. The problem can be reproduced in Winamp by unchecking:
Preferences -> Skins -> Classic Skins -> Classic Skin Options -> Always
show Winamp "Clutterbar" in main window. This part of the skin is documented on the Winamp wiki. (There it is called the CuttleBar.)
You can download a fixed n3ON skin.
I also created an alternate fix which keeps the same appearance even when the Clutterbar is hidden. It is not useful for Winamp, but it could be useful for other applications which can't show the Clutterbar. To use it, extract the .wsz (which is just a zip file) and replace TITLEBAR.bmp with the one from the alternate fix zip. You can then simply move the n3ON directory into the Skins directory.
n30N was created by deaddreamer, Wilhelm Steiner. He gave me permission to distribute this fix. Note that what I did is just a tiny bit of work; all the credit for this skin goes to him.