Dvorak - of course. He was a great one I left out. The 7th symphony, the 9th of course, many others. He was probably as much a master of orchestration as Tchaikovsky whose orchestral treatment he reminds me of.
Bruckner is one of my favorites purely as a composer, though some people take issue with his orchestration, accusing it of being "block-like" as if too much influenced by his organ background. I don't agree with that and really like it - especially the extreme dynamic contrasts he was so fond of between tutti ff and pp solos, the majestic brass writing, and the great soaring string lines. His music was infinitely simpler than Mahler's, almost as if the simple spirituality of his nature (being a very devout countryman who only moved to the big city) and his love of nature were reflected in the rock-solid, huge forms of his symphonies.
Whereas Mahler - a Jew who converted to Christianity, a neurotic but very sophisticated urbanite, was reflected in the restless, even agitated qualities of his music which had the deepest lows and highest peaks conceivable. The 6th symphony in particular is a tremendous, surging dynamo of everchanging emotions.