Piece you own the most versions of?

This is for the physical media sickos out there, but what's the piece you keep buying versions of? I just crossed into 10 different recordings of Quatuor Pour La Fin Du Temps, and I must have 6-7versions of Sibelius' Violin Concerto, Bartok's String Quartets, Music for Strings Percussion & Celesta, and the Stravinsky's Rites of Spring.

Certainly buying more than a few CDs/LPs means you end up with multiple versions of pieces, but what are the ones you search for? Are you looking for reputation? Rarity? Novelty?

Also, no idea if these are rookie numbers, I have to imagine folks out there have dozens? more? less?