Been listening over and over to Shostakovich's 5th Symphony, really great music that I have discovered a love for since my brother introduced it to me. Also, from the same source, Mussorgsky's Night on Bald/Bear Mountain, which is also really good music. Smetana's Ma Vlast is also amazing music, if a little long. Definitely recommend all of the above.
Went to a live concert of Tchaikovsky's 5th Symphony, by the MSO last week and it was AWESOME!!! I absolutely loved it, it's an amazing piece, and it is beautiful live, particularly the second and fourth movements.