1) any of a handful of Blonde Redhead concerts I attended in the mid-90s in NYC, starting with when I saw them at CBGB's on my first visit there. The only time in my life that I felt like I was witnessing something truly historic and great, like (as I imagined) how some must have felt seeing Hendrix in London early on, or Pink Floyd early on... you get the idea.
2) Gang of Four at The Limelight, around 1993. Entire set from "Entertainment" and "Solid Gold." Unbelievable.
3) dEUS at Brownie's NYC. The "In a Bar, Under the Sea" tour. Amazing.
Those are the three that immediately jump to mind... more would require too much thought to sort out!