yeah, we're guessing at this point that it's Diamond Jigsaw, as that's gotten the most attention on UWLive diaries outside of Between Stars.
Edit: Actually, I think we can be pretty certain that it is, in fact, Diamond Jigsaw. Here are some lyrics for Diamond Jigsaw:
http://www.underworldlive.com/archiv...ile/090626.jpg
And you can clearly hear the lyrics "that you finally found yourself" at the 0:41 mark here at Torino: