I''ve always said that we peaked in Jo'burg in 2002 when we crushed SA by an innings and 800 runs. I loved that team. Yes. Loved.
Langer
Hayden
Ponting
MWaugh
SWaugh
Martyn
Gilchrist
Warne
Lee
Gillespie
Macca.
Looks good, doesn't it? Actually, however,
Gillespie was in a year-long rut at that point,
Mark Waugh was finished by then,
Stephen Waugh was no longer the force of old, and Lee, as we know, was absolutely rubbish around those times.
It's a very, very complicated question. There's no doubt at all that the batting peaked around 1993...
Taylor
Slater
Boon
Mark Waugh
Border
Stephen Waugh
Healy
But the bowling in those days wasn't as powerful... Warne, McDermott (when he was off the operating table), Reiffel (when he was off the operating table) and the transition was just happening between Merv Hughes (who was finished by then) and McGrath (who was poor for his first 10 Tests or so).
The best bowling-attack, pretty well beyond question, was in either 1999\2000 or very briefly in 2004: McGrath and Warne were ever-present, and Lee in 1999\2000 was either very, very good or having beginner's luck; Kasprowicz in 2004, of course, was on an inspired return. Gillespie was there and in top form in 2004, while Fleming was in his very short spell as an established player in 1999\2000.
All-in-all, the best team was probably that of 1999\2000 - perhaps not concidentally the one that won 16 in a row:
Slater
Blewett
Langer
Mark Waugh
Stephen Waugh
Ponting
Gilchrist
Warne
Lee
Fleming
McGrath
There's just one weak-link there, Blewett at the top of the order, and just one (Lee) who will (probably) not go down as an excellent player.
Like with the West Indians of 1976-1986, however, there was no one point when the team unquestionably peaked, nor one where there was no weak-link.