Mine would have to be Queens of the Stone Age. I saw them during the Lollapalooza tour in 2003 and after their set my ears were ringing for 15 minutes. I saw them later that year opening for the Chili Peppers, and I was sitting much further away, but the result was the same. They definitely crank their amps to 11 when they play.

All I have to say about this is I am taking earplugs when I go see Explosions in the Sky at the end of this month. I have enough ear damage from machine guns and bombs to last me the rest of my life.

Slayer

Easily Dinosaur Jr in July. I was right up front, ( I mean it, no one between me and the stage). Mascis and company bring the noise, man. My ears were ringing til the next day.

Explosions in the Sky.. and The Cure. Definitely.

When I saw Dream Theater we were in this theater with terrible acoustics and I was right near the guitar amp. I thought I would go deaf.

Though it really didn't seem any louder than most heavy shows I've seen, supposedly Korn set some sort of record for loudest concert when I saw them several years ago. I remember reading article about it at the time, and while the show was certainly loud as fuck, it didn't really make my ears ring at all. I've always wondered what was up with that.

The loudest show I was ever at by my own perception was probably Metallica at Lollapalooza 96. My ears continued to ring for over 3 days, I was scared at the time that my hearing actually wasn't going to come back, and I'm pretty sure it did some permanent damage.

AC/DC - I wore earplugs and my ears still rang into the next morning. My brother, who went with me and did not wear plugs, had his ears ringing for three days.

iron maiden with frehleys comet opening

idlewild while opening for pj. too loud to hear

The loudest concert I remember though, was the Summer Sanitarium '03 show in Washington, D.C. The Deftones were the first band we saw, and they were the worst. The bass was turned up higher than any bass I have ever heard of, and you couldn't hear anything except for this enormous thundering vibration. The bass was so fucking loud you couldn't hear the guitars or the singer, it was unfuckingbelievable.

And something that happened during Metallica's set definitely qualifies as the worst/loudest thing I have ever seen at a concert. Me and the two guys I was with managed to push our way up to about 7-8 rows of people back from the stage. I don't remember what song it came after, or if it was after the encore break, but they did that intro to One. With the explosions and all. Oh my fucking god...it scared the living hell out of me. Those things were so fucking loud, I thought the concert was being strafed by gunships. Not only were the pyrotechnics louder than putting your face in a jet engine, they were so fucking bright I had to cover my eyes. Once the initial terror wore off and I had scraped my jaw off the floor, that is.

Basically, I hate anything that is too loud and/or sudden, because it brings back memories of things I don't want to remember. Fucking pyrotechnics

definitely the black crowes back in the summer of 2001 at the fargo civic center. small venue, loud tunes, and being really drunk so i didn't care about being six rows from the left tower of speakers resulted in being hungover and having my ears ringing for the next 24 hours or so.

metallica at vet stadium in 2003 or in flames at the electric factory

During the spring I went to this punk rock show with a friend of mine because his girlfriend worked at this place called the HYAMP. Well it's just an old building that used to be a printing company I think. Anyway, it was rather small. I don't even remember the name of this band, but it about blew my ears out because I was literally standing right in front of this gigantic speaker. It probably wasn't that loud from farther aloud, though.

Tori Amos, also.

Motorhead

Tortoise, Bonnaroo '03.

The bass was fucking unreal. I could literally feel it emanating from the speakers and touching my skin. And the set was outside! Half the crowd walked away within the first three minutes. They missed a hell of a performance but my hearing has never been the same.

Lollapalooza '96, the first band at Randall's Island was called Psychotia or something. They were horrible. Anyway, I was WAY back in the stands if you've ever been to Randall's Island, so I was far away from the stage and that band played SO fucking loud and their was SO much shrill feedback during their set, I couldn't hear for 3 days afterwards. If only I was unable to hear for their set.

indigo girls

Same here. I've seen my share of bands and they were far louder than any other.