Atterburg 8. It really doesn't get much better.
Gliere 2, Kabalevsky 2, and (though not an unsung, the piece is) Rimsky-Korsakov 1 also come to mind.
Gotta love those Russians I guess...
Oh and I guess Myaskovsky 19, though it's for Wind Ensemble. And for something a bit more modern but still fully in 'our' idiom, there's James Barnes's 3rd...though as far as wind ensemble pieces go that's probably not all that unsung.
Gliere 2, Kabalevsky 2, and (though not an unsung, the piece is) Rimsky-Korsakov 1 also come to mind.
Gotta love those Russians I guess...
Oh and I guess Myaskovsky 19, though it's for Wind Ensemble. And for something a bit more modern but still fully in 'our' idiom, there's James Barnes's 3rd...though as far as wind ensemble pieces go that's probably not all that unsung.