Watched (well, mostly listened) to Let Us Burn during work today. I really, REALLY like the Elements show. So much so that I watched it twice. And the crowd is SO into it that, whenever I looked up and there was a crowd shot, it instantly just made me smile. That happened several times. The fact that it has 8 songs from my two favorite albums, and a rare "bonus" track that I don't think was played anywhere else, really make it a strong set. If the video editing wasn't quite so frantic, this might easily be my favorite live collection from them.
As mentioned above, the Hydra set is so much weaker. But it still has some really cool moments. Silver Moonlight and What Have You Done are kind of unexpected highlights for me.