Loudest concert I've been to that made my ears ring for days was Black Rebel Motorcycle Club at the Civic theater. It was a combination of loudness and a poor sound engineer that made it hard to enjoy. Ears rang for a few days after.
Worst loudest concert was the Go! Team at the Black Cat in DC where distortion, loud volume, and a terribly designed acoustical space combined to make it painful to listen to. I had to resort to tearing off pieces of cocktail napkin and making impromptu ear plugs. It helped but only modestly.
Best loudest concert was Front 242 at the Mammoth. I had ear plugs for that but they just didn't matter. Bass you could feel deep inside your guts. Chest getting hit w/ soundwaves and I was mid-crowd.
I have tinnitus in my left ear and it's a constant high pitch frequency. Sometimes it bothers me sometimes not. I have to have absolute silence when I sleep because even white noise machines bother me.