The concerts throughout the symposium were dead good. My #1 highlight was the performance by Electronic Hammer, a trio of two laptoppists and a percussionist. I'm a sucker for rhythmic stuff and theirs was really really well performed, including some composed pieces plus an improvisation at the end which developed quite quickly into something really cool.
Also interesting was an extended-flute piece by Marko Ciciliani. I like it when people make instruments do weird things, and the flautist really did make some great and unexpected noises out of that flute.
The wavefield synthesis concert was fascinating, especially as I hadn't experienced wavefield synthesis before - the 2D spatial clarity of the sound was really impressive. The pieces were interesting and varied, although as Tom Hall knows, his piece will be remembered especially fondly because of the drunk who wandered in and started muttering and rambling, on and off. It went surprisingly well with the music, and lots of people asked Tom afterwards if he'd planned it :)