Since this is my thread, I guess I better nail my gig colours to the mast.
1993, Thebby Theatre - Faith No More on the Angel Dust tour. Great material, classic line-up (Jim Martin!!). There's something to be said for bands that have internal disagreements going on, as they did at the time, because it made them play like they were possessed. The material was angry enough, and the band channeled so much energy into their performance.
IIRC someone threw a drumstick back on the stage, which hit Patton. He wasn't too happy and asked the audience who threw it, and if he found out, he stick it up their ar$e. The encore included "Easy" (naturally, a big hit at the time), and a fantastic jazz version of the Dead Kennedys' "Let's Lynch the Landlord". At the very end people on the floor noticed Molly Meldrum sitting up in those balcony seats on the side, and before too long the chant "Molly's a wanker" had erupted throughout the venue. I also recall that when I turned up prior to the warm-up act (Kinghorse, I think, a band who tried to sound a bit like FNM - I really only recall a keyboard on stage) someone had chundered right in the middle of the floor. Good times!
Radiohead at Rod Laver in 2012 was super impressive for a band who's best compositional days a probably behind them. Played great, excellent sound, and the on stage visuals (dancing and rotating video screens) worked well with the material.
I also saw Nirvana in 1992. Not the greatest gig, since Kurt was apparently 'sick'. Good fodder from impressing next generation grunge youngsters, though.
Finally, Them Crooked Vultures (super-group with John Paul Jones, Dave Grohl, and Josh Homme) at Festival Hall in 2010. Like all supergroups, the collective musical outcome isn't as good as their individual talent. It was great to see Grohl pay drums again, you could tell he was living out his Led Zep dream playing alongside JPJ. But best of all, I got to see JPJ, the best bass player in rock - period. I'll never get to see Led Zep live, so that was the closest I'll get.