I'm with William ("The Season") Goldman on this one, as he wrote in Variety:
"I have gone to the theatre for 60-some years. And, yes, I was there for Brando in 47 in Streetcar.' I was there for Merman in the legendary gypsy run-through of Gypsy.' But nothing prepared me for Hugh Jackman."
HJ's Peter Allen was THE male performance of the century, at least so far.
I think PianoMann nailed it. The show probably didn't run long enough or was as well attended as needed to qualify the performance as iconic but Tracy Letts' George in Virginia Woolf should be. I saw and liked Bill Irwin's Tony winning performance but Letts was positively electrifying. I've rarely been that mesmerized by a performance. Truly memorable. I would place Nina Arianda's performance in Venus in Fur in the same "probably not in a long enough running show but should be considered iconic anyway" category.