Anyway, 50,000th Track was by 野本かりあ (NOMOTO karia) – Boombastic Hip House Band, the intro for her album "Dance Music". I liked the song "FMSB" more, since this is just an intro D:
Oh well, here's to more years on last.fm!
EDIT: last.fm just did a "played tracks" re-boot, and I am now 250 tracks under 50k. Let's see what my real 50,00th track is!! Now I wonder if my 40,00th track really was my 40,00th track??