Yes, we're blessed with some amazing driving roads.
My personal favourite is the Hilltop Pass on the R40 between Nelspruit and Barberton S25°35.417 E030°58.767
It used to be a horrible and dangerous piece of road, but it was totally rebuilt in 2009 and now it's superb!!
Coming in a close second is the R40 between Barberton and the Swaziland border. The first few kms up Saddleback Pass is badly potholed, but from there on the next 30kms is brand new tarmac build for 2010 World Cup Soccer. Stunning mountains, steep gradients and sharp well cambered corners, smooth road surface, and almost no traffic. From S25°47.870 E031°06.230 southwards to the border.