Hmmm, i should get around to putting up a trip report of my recent trip as i see bits and pieces that would help several people with their questions..
Can't claim to be an expert but flew down from Europe to JNB and to be frank spent the two days in the hostel, didn't really feel safe to go out travelling, this may have been coloured by things i had heard and i chose a place to stay in the wrong place to allow easy access and couldn't work it to meet up with a friend i had met on facebook.. But as quite a few people say JNB is nothing special so I don't feel to bad about that, but may be nice if you know what your doing...
From there flew up to Livingstone which is the Zambian side of Victoria Falls and stayed in a hostel, felt like a reasonably safe town/city, helped that i met a few people at the airport on the bus into town and bumped into them several times and did a few things with them... Anyway walked around town quite easily, took the hostel bus to the Falls for a day visit, did a cruise on the Zambezi, did a microlight flight over the falls... Didn't see to many flash hotels but then i think they were out of town a bit closer to the Falls... Glad I chose not to do a bungee jump after reading the story of the Aussie girl who jumped around new years and the cord snapped and she fell a hundred metres into the Zambezi and had all sorts of bruises etc over her... Me being a budget traveller i flew up their on One Time Airlines (not the most reassuring name i know

) but it was fine and cheap... Around South Africa I also considered flying Kulula to see if i could get that cool painted plane of theirs, but One Time was a little cheaper...
From Livingstone i also booked a two day/one night camping tour across the border into Chobe National Park in Botswana where i saw the elephants and giraffes and all, which went well, no issues of safety, i could have done a longer one of 3 days/2 nights, i could also have done a tour where i stay in a hotel of sorts rather than a tent, each cost different amounts but were easy to book...
Flew One Time back down to JNB and then SAA down to Cape Town which seemed relatively safe in the centre of town with quite a few sort of locals patrolling the streets, i guess they are some sort of hired guards, not police, which watch over many of the streets... As long as you don't do anything silly or walk around with heaps of bling etc, i think you would be ok, but would keep your wits about you... I stayed in a hostel again but there did seem to be some nice hotels... I got on one of those hop on/hop off circuit buses and took it up to get the cable car up to Table Mountain for some spectacular views of CT and saw a few other parts of town...
Wouldn't have minded fitting in Durban but didn't have time... Wouldn't mind going back to South Africa, maybe to Cape Town and then take a tour up into Namibia.. Also wouldn't mind going to Kenya/Uganda/Rwanda sometime as well although those places might be a bit dodgier than down on South Africa... Nice to have plans for the future...