Funny you should say that...
As my name suggests, I'm also a DJ (or at least I used to be, semi-retired now).
I Dj'ed for ~20 years (clubs, festivals, fm radio) and have a collection of approx: 20,000 vinyl, 5000 CDs, 10,000 cassettes, and 12,000 mp3/ogg/etc.
I tag all my files as and when I encode them.
I used CDex or EAC prior to Winamp supporting --alt-preset Lame, and naturally set up the prefs to make sure that all the files were placed in their correct folders when encoded, and used cddb to tag them all prior to ripping.
Any files I've downloaded were via the likes of allofmp3.com and emusic.com etc, which have download managers that correctly tag, name and store the files according to taste.
The few that I downloaded with the likes of WinMX/Soulseek/emule, most of them were such shit quality that I ended up reacquiring them in top quality ogg or --alt-preset standard lame mp3, and the few I kept were all manually renamed, tagged and properly stored in aptly named folders prior to importing them into the Winamp library.