For Wagner: Joseph Keilberth
For Mahler: Bruno Walther
And for just about everything he touched: Thomas Beecham
There's a story told by a well-known conductor who was rehearsing the BPO in Bruckner and just could not get them to sound the way he wanted. Suddenly, a few minutes into the problem passage, he noticed that the orchestra's performance seemed to shift into a higher, more intense gear. Surprised and confused by this sudden change, the conductor looked around to see Furtwangler standing quietly in the doorway of the auditorium.