Hard to decide, because they're all pretty good. But which do you think is the best one !? My choice, The Mystic Forest

Here's a list of audio-only youtube videos for those who don't have the songs nearby :
Tina
Gau
Kefka
Spinach Rag
Stragus
The Mystic Forest
Kids Run Through the City corner
Johnny C. Bad
Mystery Train
The Decisive Battle
Coin song
Celes
Waltz de Chocobo