Favorite conductors for composers

It's tough to go wrong with Leonard Bernstein with anything. Feel a hankering for those Russian ultra-romantics Tchaikovsky, Rachmaninoff and Rimsky-Korsakov?  He's your man.  Bruno Walter truly unearths the souls of Beethoven, Brahms and Gustav Mahler. I think Bruno Walter actually knew Gustav. Walter's records have surprisingly good fidelity, too. Neville Marriner finds suavity, energy & grace with Mozart and Haydn.  He makes the tunes those guys wrote really sing. Try Gustav Leonhardt for J.S. Bach. No fuss. No muss. Get up and dance. Benjamin Britten was not only a superb composer, he could really swing a stick. It doesn't hurt that London-Decca gave Britten's efforts some of the best sound quality you'll ever hear.

Another vote for Karajan's Beethoven. His 1963 cycle is a masterpiece.
Bruno Walter and George Szell also for Beethoven.
Mahler...Bernstein, Walter, Furtwängler, Boulez, Claudio Abbado.
Bruckner...Furtwängler, Giulini.
Brahms...Bruno Walter, Toscanini, Carlo Maria Giulini.
Tchaikovsky...Bernstein.
Sibelius...Karajan, Eugene Ormandy.
Schubert...Edward Gardiner, Charles Munch, Claudio Abbado.

Vladimir Ashskenazy for Shostakovich, Tchaikovsky, Rachmaninoff.

Bernard Haitink, one of the best modern conductors.

Colin Davis and the BSO for the Sibelius symphonies. 

Daniel Barenboim and the CSO for the Bruckner symphonies.

Bernard Haitink for the Shostakovich symphonies.