Kenneth Tynan (the British theatre critic & general 'commentator') used to write about "high-definition performance", and this comes pretty close to the IT we're talking about here. He listed, among many others, Dietrich, Noel Coward, Muhammad Ali, Eric Morecambe....

Some good suggestions made here (though I boggled at a few - Richard Branson???). I'd throw in a few more:

Mariza
Estrella Morente
Martin Luther King
Martina Navratilova (playing tennis, sadly a bit dull off the court)
David Bowie
John Lydon
Eric Cantona
Ken Dodd
Margaret Thatcher (and I sooooooo wish she hadn't, but she did)

And returning to the start of the thread, Amy W undoubtedly had it.