Hi Michael,
Well, its a very hard and interesting question !! I have personally listened to not all recorded versions, BUT, we all have our distinct favourites, but my "desert island disc" on Mahler"s ninth would have to be Bernsteins"s 1960"s NYPO on CBS. (the later DGG just doesnt do it for me) I used to love the cover of the black Raven on the LP box set ! But the playing is spot-on I think,the basses just transport me. I know Lenny (and I miss him terribly) is often criticised for being "over the top" but this version is always the best for me ( as his Mahler 8th too!!!,,,CBS)
Regards Jack