I've never sledged anyone in my entire life but other than racist or otherwise personal taunts (which is entirely subjective and the umpire should regulate out on the field), I don't have any problem with it.
The higher standard you reach, the more it gets too. It's all part of the game (or any game for that matter).
I tell you what, though, I think it's a sad day for cricket when a South African, given their deserved reputation as hard and tough competitors, is complaining about sledging. Maybe this lack of toughness is a reason for their demise? Could any of you imagine someone like Gary Kirsten, Fanie de Villiers or Brian McMillan complaining that any team sledges too much??!?!?!?
ALL of the Test-playing nations sledge. It's a fact borne out by people I know who've played against most of these guys and have listened to recordings taken on the ground, only for these same players to complain the Aussies sledge too much. It infuriates me no end when I see someone like Roshan Mahanama complain about Aussie sledging when he was one of the worst offenders (and was unsportsmanlike; anyone remember him hip-and-shouldering Darren Gough out of the way in Adelaide whilst going for a run-out a few years ago?). And it was also hilarious when Ranatunga used to complain about sledging too; do people really think he got his reputation as a hard-nosed competitor JUST because he could bat well?
So yeah, the Aussie players have been demonised a little in the sledging department but only because every other team does it too. And legislation against it is pointless and discriminatory because it's usually enacted by people who've barely touched a cricket ball before or who are so out of touch they think Geoff Boycott was a reasonably attacking player.