Classical in general is not my favorite, far from it, really (I'm into metal...). But some of my overall favorites are classical.
Adiago for strings in G minor by Albinoni
Lacrimosa by Mozart
Winter from The Four Seasons by Vivaldi
La Mer by Debussy
Minuet in G minor by Bach
Ouverture from Suite for flute and strings in A minor by Telemann
I love Telemann Suite, but I haven't been able to find it ANYWHERE. If anyone knows where I can download/buy it, I'd appreciate it. It's a really gorgeous piece, and I'm proud to say I can play it on the flute! It was the honors band audition piece...
And I can play Bach's Minuet in G minor on the piano. It's pretty, easy, I know, but more of my playing style...
So, yeah, overall it has to be powerful and minor for me to appreciate it. :)