They were all amazing.
At the last concert I was near the speakers and I nearly went deaf. They sound so different live, even the slow, quiet songs turned into screaming, guitar-driven monsters. Phenomenal. Nick jumps around the stage so much in his usual frenetic mode that he once tripped over the monitors and nearly fell of the stage. Never stopped singing though.
On the other three concerts I positioned myself right in front of his mike, so he was 3 feet away from me.
I still have battle-scars though. My bruises as I was pressed against the rail wouldn't go away for weeks. But it was all worth it.