Err, I know pretty much every South African line-up of the last 10 years. The team of 2001/02 had Kirsten, Gibbs, Kallis, McKenzie, Boucher, Klusener and Pollock, quality players all. They also thought they might have Donald, though sadly they were mistaken (he did play, but he wasn't the real Allan Donald any more). That they didn't make the Super Six (not Eight) of WC2003 was a) totally irrelevant as that's a ODI competition and the Australia Test series was, astonishingly enough, a Test series and b) not due to the inadequecies of that team.
As for 2005/06, Smith was less out of form than merely not playing terribly well at that time. The way he repeatedly played at wide deliveries, something he virtually never did in 2003, and something he's still doing far more than I'd like to see right now, caused him near enough all his problems. Kallis suffered with an injury in a whole 1 Test (and though he played 2 good innings', he was wrongly criticised for not upping the pace despite being pretty well incapable of doing so thanks to his lack of fitness) and simply did not bat as well as one might hope he would. ABdeV was a decent player, so was Prince, neither of them performed - it happens. Kemp played a whole 1 Test.
Now, there is Smith (who as I say has still not completely convinced me the way I'd like him to have), McKenzie (who has still to convince as an opener, pretty well all his big runs coming on stupidly flat wickets), Amla (who has still to convince full-stop), Kallis (who's just had a poor series where his long-standing failure to sight very full balls has been exposed, a weakness you can bet your life the Australians will look to repeat exploiting and which I hope he'll make an effort to address), Prince (a good player but who might have put all his eggs in a basket for now) and de Villiers (an opener batting at six). That could be strong, but it could be weak as well.
And the bowling-attack remains very much to convince. The fact that the bowler with the skill to do best, Nel, remains the worst performing, says it all.