I would have to say Pantera in 1994 on the Far Beyond Driven Tour..I'm not sure if anyone can match their intensity. It was amazing and with Darrell gone, I feel fortunate to have seen him play live.
I probably can't pick a single event but heres a couple. Tool in New Orleans. Against Me! at a bar downtown a couple years ago was by far fun as shit! I've seen the Allman Brothers a couple of times and enjoyed each. Front row of a Lil Wayne concert (lmao) but it was pretty crunk to be honest. A couple bands I want to see bad are Red Hot Chili Peppers and Modest Mouse, shit will happen!
Back in 1989, Queensryche (Operation mindcrime), Metallica (And justice for all) concert. Saw them in Rochester and Syracuse...Fucking Rocked! My favorite albums from both bands and I hooked up at the Syracuse show.
bobby hutcherson all stars, mccoy tyner, primus at the palladium in like '93, trans am at the echo on the TA tour, steel pulse, and best of all probably was Burning Spear.
I saw nofx at warped tour in dallas and they played the entire decline (something they said they would never do live). If your a fan of this band you know how big of a deal that would be. honorable mentions are RATATAT and the HIVES both were great shows. Muse was awesome also.