Oh, that's really hard with Tchaikovsky, but I'd have to say the 1812 Overture followed closely by March Slave. Both are really mvoing peaces for me, although in different senses. Personally,I love how March Slave starts off very somber.
BTW, love the Futurama quote in your thread.

That was such a great episode.

Masterpiece: I was looking at a few people's opinions on what Cosmonaut meant- very intruiging. Many seem to think it's referencing the TWA plane crash and the cover up from the government. Very interesting.
I LOVE One Armed Scissor- it's such a great song. What do you think they meant by it, though?