WinAmp 2. I still use Audacity in "classic" mode to make it feel like WinAmp.. Old habits die hard :)
Going further back, I think Symantec JustWrite was an extremely fine piece of software; I remember it being blazingly fast on the 486 monster I had at work. But my glasses may be rose-tinted :)
The big thing I liked about Winamp was the equalizer. It should be built into streaming apps. I think Spotify has one, but it's not advanced enough. It would help my car's mediocre settings and speakers, also.
You're not the only one - check out https://getwacup.com/ for a more modern version. The new offering from https://winamp.com/ is - I think - going to be mobile-focussed? A new codebase entirely?
Webamp can also do Milkdrop visualizations, which is pretty crazy - eg https://webamp.org/?butterchurnPresetUrl=https%3A%2F%2Funpkg...
I had a link I've since lost to one which was a shader-skin, which mirrored milkdrop back into the rest of the UI. It was pretty trippy, and wholly unexpected!
Depending on the use case (mine is really simple--play music with basic playlist management), QMMP is also a really good replacement and is well-maintained.
Going further back, I think Symantec JustWrite was an extremely fine piece of software; I remember it being blazingly fast on the 486 monster I had at work. But my glasses may be rose-tinted :)