Dreaming is OK, but the best arrangement in the game IMHO is Tension.



DISCO TENSION!!

I can honestly say I've never heard a disco-based boss battle theme in any other RPG... and I totally love it.

I also really love the Origin version of Devil's Wind:



If only because they took a 3-second loop from Ys I, and made a whole song out of it. And a good one, at that!

-Tom