I have thoroughly enjoyed reading about others' experiences in this thread. It's been great to live vicariously through you all.
In no particular order...
Okay... all the New Kids on the Block concerts I went to. NOT because of their music *shudder* but because I was 13 and in love with them and every show (I saw them 3 times) was an
event with my then-best friend Amy. Fom ordering the tickets on Ticketmaster to picking out what to wear, to the drive down (bless our parents for withstanding the sometimes three-hour drive with us listening to NKOTB at full volume and squealing the whole way), to the sheer adolescent bliss of being in the
same (giant, yawning, cavernous arena)
room with these famous, attractive (of mediocre talent at best, but skilfully marketed as a product) young men.
Musically, pretty devoid of anything. Nostalgically, priceless, and therefore worth mentioning.
Also:
The two times I saw Dave Matthews it was early on in his career. Late enough that he was already uber-famous (they were arena shows), but early enough that his stuff was still new. I have since fallen out of fascination with the DMB because all of their music sounds the same. However these two shows were a good time. The first time Ben Harper opened; the second time Maceo Parker opened (I think, I may be confusing this with another show... more on this later). Notably, I remember Harper and Parker more keenly than DMB. Maceo blew my mind.
Part of the reason the Maceo show was so great was, well, it's Maceo Parker. But also a friend's band,
Phat Phunktion, was opening for him. PP is an amazing group of musicians, and it was awesome to see them in what was for them at the time such a huge show. I remember PP, I remember Maceo; but I can't remember if they were both opening for DMB or if that was a separate show. Goes to show you how un-memorable DMB was.

I saw Seal at an outdoor concert in 95 or 96 and it was an outstanding show. Every song he sang was moving and the production quality (lighting design, etc) was just gorgeous. Everything enhanced the performance without being gimmicky. It was just a beautiful experience all around, and I was transported. The music was immersive and everything else fell away except for what I was hearing and seeing and feeling (emotionally and tactilely) at the time. And I didn't have any kind of mind-altering substances in me at the time. The show itself did that all on its own.
Pretty much any show I've seen at my alma mater's
Memorial Union Terrace ranks up there. The band names, save for a few, are gone from my memory (thank you cheap beer in a paper cup), but the fuzzy memories are awesome. I got my first mosh pit black eye at a show there, I think at a Little Blue Crunchy Things show, which is funny because they're not a band one typically moshes to. I suppose it was more like a "skank pit" (that sounds horrible), although they're not really ska either. I took an elbow to the eye. It was awesome.
In the enjoyable but not necessarily molecular-structure-rearranging category: Queensryche, Rush, The Cranberries, Harry Connick, Jr (twice; once with orchestra, once with a small jazz combo), Wynton Marsalis (utterly disappointing), U2 (outstanding, during the Pop Mart tour, but it was a huge arena experience and therefore somehow "less". From a visually artistic standpoint, the lighting design was fabulous).
Totally disappointing: Sting. Quite possibly the biggest letdown ever. It was business as usual for him and I sort of felt like I was in the doctor's office rather than at a concert. I realize that for musicians, performing is their job, but for the rest of us it's entertainment. If I want to watch someone doing a job, I'll go down to the local widget assembly plant and get a visitors pass.
I saw KISS maybe 10 years ago at our local arena. I went because I sort of felt like they were one of those phenomena one has to see in life--like the Grand Canyon or the World's Largest Ball of Twine. For me it was an exercise in cultural anthropology. They were no longer in makeup, and they were sorta fat and old. Their fans were too, but many seemed not to have realized it. Women still tossed their bras on stage--women who should not be removing their bras in public (I think there were seismic disturbances as a result). The performance of "Beth" was positively geriatric. Honestly, I felt like I was at an open mic event at a nursing home. But they still had cheesy pyrotechnics as they hobbled around. I'm glad I went, although I remember none of the show per se. It was a cultural experience.
To return to concerts that actually changed me, Itzhak Perlman. Outstanding. I think I held my breath through the entire performance. What struck me was that he was so humble; he just came across as a regular guy. He spoke briefly with the audience before each piece, and he was just this soft-spoken dude, kinda portly, and then he started to play and you just knew you were in the presence of a Presence. He
became the music. It was unbelievable.
Coldplay at an outdoor show was great too, not because of the music necessarily, although that was very enjoyable, but because of the circumstances. A friend had a bunch of extra tickets and rounded up a crew of friends and acquaintances the day before. We figured, "What the hell, why not?" and headed down to the venue. We only knew my one friend in the group, so we met a bunch of new people that day, which was fun. They had gotten there early and had set up a little grill and stuff, we all brought things to cook up and eat, a bunch of beers, frisbee, hackey-sack, etc. So we spent the afternoon with essentially total strangers, barbecuing and playing lawn games, chatting, generally chilling. Then we spread out our blankets and watched the stars and listened to the mellowness that is Coldplay. For all I know they could have just been playing a live album over the sound system. I didn't actually pay attention to what was happening on stage. I was lying on the grass looking up at the sky and just letting the music happen around me. Nature was the show and it was beautiful.
Lollapalooza, 1993. It was my senior year in high school. The local top-40 station was broadcasting live from outside the building from where the local college station was broadcast. This in itself was funny because the top 40 station was, well, top 40 (yeesh), and the college station was really alternative, in the truest sense of the word. The top-40 station was giving away tickets to Lollapalooza so my good friend and I skipped our first period class to go down to the site and try to get tickets. The DJ's said we had to do something to earn the tickets and so we dug around in my girlfriend's car for several moments trying to find inspiration for what to do to get our tickets. We were both in drama club and figured we could make an event out of anything, with the right props. We finally settled on a box of Kleenex and agreed to eat the kleenex to get tickets. This seemed to satisfy the DJs and so we each ate a couple of kleenex each. It wasn't bad.
Prior to the show there had been massive flooding in the outdoor park where the show was to be held, so they moved it to an indoor arena. The mosh pit was insane, particularly for RATM. I'm a tiny person (5' 2" and about 110 lbs), so I kind of felt like I was going to be killed, which was awesome in that scary way. I held my own, sorta. During Arrested Development the crowd pressed in so tightly that I got pinned up against the barrier and couldn't breathe. Also, a guy behind me kept copping a feel. At first I thought it was just because of the crush of the crowd, but then when I realized his hands were actually groping my boobs, he got an elbow to the nuts. By the time Primus came to the stage I was exhausted, but in the awesomest way possible.
The absolute best show of my life, though, was giraffebone at a small venue in Chicago in, I think, 1995. Again it was one of those things where the experience surrounding the show outweighs the show itself (although the show was pretty awesome). A guy I was into but not yet dating, and pretty much all his friends, arranged the details. There were probably 15 of us in all. We piled into several cars and drove down to Chicago. The best part was that I had no idea what would happen. All I knew was that at such-n-such a date, we were going down to Chicago to see giraffebone with some people. The road trip itself was a blast--the kind of stuff people talk about on a road trip in their early 20s is the stuff that makes me glad to be alive in this place and time. We had booked a suite in a little boutique inn in the middle of the city. To this day I have no idea where the hotel is or what it was called. It seemed to me like it was this nondescript brownstone building in the middle of a residential area. We had to have two of the guys check in and then go around back to sneak the rest of us in with all our stuff (which included several coolers of beer). We bummed around the neighborhood for a few hours. I don't remember what we did for dinner; seems we either ordered pizza or found this little dive Chinese place... but it escapes me. Then we started walking to the club. I had no idea where we were going so I just followed the crew. That was the best part--not having any idea what would happen next. It seems we walked for something like 20 blocks or more, and then all of a sudden we were in this teeny little music theatre that looked like its heyday had been showing vaudeville acts in 1910. The opening act was Weapon of Choice, and I totally got my funk on. They warmed up the crowd and the guy I liked was starting to put the moves on me.
Then giraffebone came out and it was the most insane rocking show ever. Again, I felt as if my death was imminent. The pit was insane, but courteously so. Angelo was climbing around on the rigging, diving off the balconies into the crowd. I got thrown around, I thanked heaven for having the foresight to wear steel-toed shoes. I think I got drunk. When I wasn't being thrown about the theatre,there always seemed to be a cup in my hand. Well, okay. Moshing does make one thirsty.
The walk back to the hotel was pure torture. After all that craziness, my feet were killing me and the twenty blocks felt like a hundred. We all snuck back into our room via the back stair case and cracked open our coolers of cheap beer. I felt like I knew these acquaintances better, somehow. We were all crashed out on the couches, the beds, the floor, the foldout couch, wherever. And shortly after everyone passed out, me and the guy I was into had some pretty nice makeouts.
The next day we all dragged our hung-over butts to a local dive diner and filled up on greasy eggs and bacon, and then walked to the Field Museum to spend the rest of the day. We'd basically made a weekend of it, and it was so Zen because I was so clueless about the plans that everything was very in-the-moment for me.
That weekend is definitely one I will revisit often in my old age, after dementia has made the current time incomprehensible to me.
I had a similar experience going to see Noam Chomsky speak (I've seen him speak three times: twice for Linguistics--yay!-- and once for politics--yawn), but since that's a lecture and not a concert, I'll save it in case a "Favorite Lecture" thread comes up.
Okay. Shutting up now.