Went on 3 week holiday there back end of last year. The trouble stories are true, but not a big issue for the average white going about normal business in a sensible manner. Being concerned beforehand we also took 'drastic' measures - dummy wallet with a few rand and fake cards, �5 watch to replace my decent one. Spent 8 days in Cape Town then 14 days on the road travelling in Western and Eastern Cape. You cannot avoid but notice the security measures that (mainly) whites take - barbed wire fencing around most decent properties, security guards. You just get the feel of the place and don't go to certain places at certain times. We felt intimidated just once - felt we were being followed an an area where there were no other walkers, plenty of cars around and daylight. Just turned around and walked the other way.
Most serious crime is black on black - and in the townships - seemed like a murder an average of a murder in a township every second night. Most petty crime is opportunist. We were sat outside a cafe when a man sat down right behind me. Cafe owner spotted it before we did and moved him on - he was bent on rifling through my rucsac. You just keep aware of people around you and what they are doing. Outside of Cape Town things were a lot more relaxed. We went to small towns with sizeable black townships on the outskirts where our B&B hosts assured us there was just no issues - people of all creeds and colours were friendly, helpful and would pass the time of day.
The Cape Flats area of Cape Town is something one can scarcely believe. Mile after mile of shanty buildings just crammed up against one another. Unemployment is incredibly high (40%) and those with no jobs seem to regularly come into town and just hang around on street corners, looking for work. Just the men, always just the men.