Don't get out to concerts much anymore, but reading this thread has brought back some fine (and not so fine) memories of past concerts. As for the good shows, the best were Tool, Liz Phair (first tour, not this piss she's singing now), early No Doubt, Radiohead/Belly (first tour), Weezer (first tour), Green Day and Shudder to Think. All, except Tool and No Doubt, were at small venues--which really are the best.
As for the worst; saw Incubus, Linkin Park and Blink-182 about 3-4 years ago and regret every minute. Maybe the CDs sounded okay at one time, but LP and Blink have absolutely no clue as to how to perform live (unless you include singing off-key and constantly smacking the upraised hands of the audience). As for Incubus, just no energy at all, and they were basically upstaged by their opening act...Hoobastank. Yes, Hoobastank
I'm also beginning to recall all the small-club concerts I used to attend while in college. Most had bands that were never very popular and are all but forgotten now. Most of the time, the big lure was the full-bar at the club...yum!
I recall seeing (I think): Little Caesar, Company of Wolves, The Four Horsemen, Junkyard, Firehouse (not Firehose) and Saigon Kick, among others that are still too foggy. I think I still have my ratty Junkyard shirt. Good times.