It's probably between:

Devendra Banhart - I don't follow his music, but he was good right up until the point where the venue had to close. The crowd weren't very happy so he went outside and gave an acoustic performance on the street!

Joanna Newsom - I was just totally transfixed. She was charming, elegant and the music was beautiful. I think I was pretty much in love with her by the end of the concert.

Godspeed You! Black Emperor - Brooding and ominous. And the crescendos! I'd never expected to see them live, as they went on an indefinite hiatus while I was in Bangor (a town not frequented by Canadian bands... or British bands... or buskers). Waiting that long and then finally getting to see them just blew me away.