Crime
When I ask first-world-people about Africa, their opinion is mostly very dark. The media is always talking about Africa when there's a civil war or people are starving, so the people in the first world always believe that Africa is a bad place to go. Good news are no news, so we never hear good news from Africa. But certainly, Africa is a good place, my favourite!
Sure, crime is very high in cities like Nairobi or, especially, Johannesburg. I didn't stay long time in Nairobi and didn't even visit Jo'burg because of its record-high crime-rate! As long as I was cycling outside cities, I felt very safe! Remember: People who are poor must not automatically steel your things!
In Kenia you should take care all over, though I never met anyone having had problems outside Nairobi. From time to time tourists are shot or robbed in one of the National Parks - this was the situation in 1994. I can't tell you how it's today.
Tanzania seemed to be a very safe place, though bigger towns should be avoided during night-time. Unfortunately, my favourite place in Africa, Zanzibar, is becoming more and more unsafe. Many thefts are reported, but this shouldn't stop your idea to go there! I heard from a dutch doctor that he saw in Dar es Salaam's central market how a mob ripped an egg-stealer in pieces! This happens with stealers in Africa every day!!
Malawi was, during many years, one of the safest countries of the world. Malawians are very warm people! Because of the heat I rode my bike during night-time and always felt as safe as cycling in Switzerland during nighttime! I only met one Australian guy who's tent and travel-equipment had been stolen in a campground. Some days later, two local people were arrested. Because they had robbed a white man, they caught 10 and a half years of prison!!
I don't know about crime in Moçambique. I crossed it two times on a truck, it took me three hours from Malawi- to Zimbabwe-border. This country finfished its civil war at the beginning of the nineties, and it's the poorest of the world. The inofficial jobless-rate was 98 % in 1994/95.
Zimbabwe is very safe.
South Africa was, in 1995, in the year after the election of Nelson Mandela, very unsafe! I was told never to cross an area where black people live, so I crossed all the mountains instead of the flat lands. Finally, just 15 km outside of Durban, near Amamzintoti, when I crossed a black area again (because it was not possible to avoid them all the time), the inhabitants of a whole village run after me and scared me to death! Later, I crossed many unsafe areas again, but never again something happened. Until today, I don't have an explanation why a whole village chased me away! Take care in Cape Town - avoid the slums and better take the highway instead when you go towards Garden Route!
I remeber very well when I climbed a steep mountain by bike in swaziland and a South African Radio station announced the good news about 1994: "The rate of murderings has dropped - now only 1 out of eight people who died in 1994 died because of murdering!"
In general: The eastern and southern african countries are not much more dangerous than european countries. The only time that something was stolen from me happened in Moshi, Tanzania, near Mt. Kilimanjaro. I was celebrating the climbing of the mountain with some new german friends in my hotel. Two days later I realized that my travelers-cheques, 700 US-$, were gone! And suddenly I remembered that I was asked that evening by one of those german fellows if he could cash traveller's cheques in Kenia without showing his passport.
So, take care, travellers might steal more from each other than local people from foreigners!