Those aren't all the original versions they are playing which kinda ruins it.. but as they appear on the system, i'd have to say..
As far as standard battle themes go, within the context of its time, FF4 still has a great standard battle theme, just beating out FF6 and FF8
As far as special themes go..
FF5: Gilgamesh battle / Bridge encounter theme all the way

.. FF4's The Dreadful Fight is also very good (its one of the boss themes, used for the 4 fiends and such).
Best overall sound goes to FF6, hands down. FF7's was very disappointing, and FF4's wasn't diverse enough.