Of the three Xenoaga games, I like Episode 1's random battle theme the most. I remember people complained that the theme was overused. Personally, I couldn't get enough of it. It was best part of grinding/farming in that game. It made even the most mundane seem epic. It also took me back to Xenogears' battle themes. Episode 3's random battle theme is my least favorite because it doesn't feel epic. I really enjoyed the boss fight music (Testament specifically).
"How to Sell a Soundtrack: First, Ignore the Movie" -Newsweek headline