If such an animal exists, I'd like to hear about it.

/tumbleweeds

I guess useable winamp-skin is kind of an oxymoron.
Oh well.

Classic skin: Hoop_life

scruffy, baby, thanks, but no thanks. That is almost, but not quite, the exact opposite of what I had in mind.

I use the Netscape skin, because I'm Netscapecore from back in tha day. But then, I've had this skin since Winamp 2.2 (I think), so I don't know if you can still find it in the wild.

I flirt with other Winamp skins, and even, a long time ago, made one myself, but Steel This Amp has been my main squeeze for years.

Alternately, my Internet pal minusbaby makes a nice minimal skin, though it's a little dark for my taste.

Did you want classic or modern? I've got a functional skin at home (I think) from ages ago. It's from the Winamp 3 days, but it's still good... made for dj's. I can't for the life of me find it on the web anywhere. 'Course it'd help if I could remember the proper name. I'll keep looking and if I've got it, I'll put up a YSI link.
What do you think of this? Effective, easy to use, great theme... http://www1.1001skins.com/skin_details.html?skin_id=441

Modern skin... maybe this'll work for ya?
http://www.winamp.com/skins/details.php?id=142370
Minimalist, but still stylish. All modes have a very small footprint on the desktop.