This is so my kind of thread.
Anyways, this is a selection of some of the classical music I like:
Bach (the J.S):
I think it's very serene, peacefull (and played by a brilliant pianist).
Mahler: I love most of his symphonies, and in particular the third, fifth and sixth.
This is the famous trombone theme from his third, well executed by Valery Gergiev and the London Symphony Orchestra:
As one might realise, when listening to Mahler he knew how to handle a large symphonic orchestra.
Also, he was almost despised by the press in his lifetime, but he rose to new heighst of popularity in the sixties, because of such conductors as Bernstein.
A famous qoute from Mahler regarding the purpose of a symphony:
"A symphony needs to be a world in itself, it must contain everything".
Apart from these two (very different) composer I like Rachmaninov (not sure i spelled that right), Prokofiev (another impossible russian name), Strauss, serialists such as Sc÷nberg and Weber and post-modernists like Stockhausen.