Now that you know the Sugar Plum fairy side, and the sad dreary side thanks to Caity, I feel obligated to share the side of Tchaikovsky that makes him one of my favorite composers.
Tchaikovsky's large symphonies and works such as the 1812 Overture demonstrate a dramatic and powerful side of his music, and are among my favorite pieces of classical music. The 1812 Overture calls for a canon in the score - what more needs to be said? After you make the French flee your country after an attempted invasion I don't think the stereotypical cold and dreary Russian piece (and certainly not a ballet) would suit the mood.
Also, I play the trombone, and over time have begun to appreciate composers of orchestral music like Tchaikovsky that create such powerful parts for the brass section of the orchestra - For trombonists, most orchestral music involves lots of waiting and counting, and not much playing.
What makes this subject even more personal to me is that I was fortunate enough to be able to see a concert entirely of Tchaikovsky music given by the Moscow Symphony Orchestra as it made a stop in
Here is a clip of the triumphant finale of Symphony No. 5:
Feel free to laugh at the conductor..