Here are some "classical" pieces that I have become familiar with over the last few months. You should acquaint yourself with them if you can.
The Planets - Gustav Holst
First Suite in Eb - Holst
Second Suite in F - Holst
Quiet City - Aaron Copland
Sonata for Trumpet and Piano - Paul Hindemith
O Magnum Mysterium - Morten Lauridsen
Quintet - Michael Kamen (for the Canadian Brass)
Sonata Pathetique - Ludwig von Beethoven
Phrygian Gates - John Adams
Symphonies 1-9 - Gustav Mahler
This should be enough to get you going for a while.