Dark World from A Link to the Past, it was really nice!
Mine is probably the 25th Anniversary Medley. I especially like the way they incorporated the theme from Spirit Tracks. One of my favorite Zelda songs. I think its safe to say I love all Zelda songs no matter how repetitive.
I agree with Tadpole. While it's still a few weeks until the symphony comes to my state, the 25th anniversary medley on the CD was incredibly epic. I rather liked The Wind Waker medley too, though.