Adding my vote for Winamp 2.95 as well. It's one of the best and most iconic media players from this time. I remember using it on Pentium 2 Dell Latitude CPi (1998) in my parent's garage around 2000, and of course finding and testing out skins. One of my favorite skins was Syrogenesis v5 (screenshot attached). I have a bunch of Milkdrop presets saved as well.
I still use Winamp today as my main local media player (alongside Spotify) but in the form of WACUP (Winamp Community Update Project). WACUP has some updates that allow it to run better on Windows 10. I use the double-size mode and it looks and runs perfectly on a 4K display. The last official release of v5.666 works okay... but I still prefer WACUP. The maintainer, DrO, was on the original Winamp team I believe.
I used Foobar2000 for a couple years, but only on a Windows 7 era rig when I was getting into FLAC, DACs, nicer headphones, etc.
Rigs: Harris 286-16 [WIP] | Am386 DX-40 | i486 DX4-100 | P-MMX 233 | K6-III+ 600 | P!!!-S 1.3GHz | XP 3200+ 2.3GHz | Q6600 3.2GHz