Ranked by an Organization:
Tunisia, Ghana, Botswana, Morocco, Mozambique, Gabon, Namibia, Senegal, Malawi, Equatorial Guinea, Egypt, Cameroon, Kenya,  South Africa, Ethiopia, Uganda , Algeria, Angola, Cote d'Ivoire, Nigeria

By tourists:
To be secure: Tunsia would probably be fine, Ghana is probably the safest in that region , South Africa,   Malawi,  Namibia, Egypt, Burkina Faso and Mali are also fine. Uganda, Tanzania, Kenya are all safe

Middle: Nigeria, Liberia, Botswana, Rwanda, Uganda

Bad: Sudan, almost all of Eastern Africa, Sudan, Congo, Chad, Somalia, Zimbabwe, and Ivory Coast

One said: the most dangerous countries in Africa at the moment are. 1. Somalia 2. The Congo 3. Sudan 4. Burundi 5. Ivory Coast 6. Zaire 7. Algeria 8. Liberia 9. Sierra Leone 10. Nigeria.  The safest 1. South Africa 2. Kenya 3.  4. Uganda 5. Tanzania most dangerous 1. Somalia 2. Liberia 3. Algeria 4. Angola 5. Rwanda

Another said: The most dangerous countries in Africa at that time are--- 1. Democratic republic of Congo (It really is as grizzly as you can imagine, but once safe, it will be an incredible opportunity for adventurous travellers) 2. Nigeria----poor reputation for street crime and carjackings. Religious tensions bubble under the surface, and mass unrest isn't uncommon - keep your ear to local news sources 3. Somalia--Somalia remains one of the world's most dangerous destinations 4. Niger--Due to the presence of bandits and militias, travellers should avoid the border areas with Algeria, Mali, Libya, Nigeria, Chad and Mali 5. Burundi--fighting is not un common here 6. Sudan---Military activity in the Darfur region is ravaging Sudan, with more than two million people displaced by the conflict so far. Avoid Sudan at all costs.
       The safest-- 1. Tanzania. (With the exception of caution for malaria or various other tropical diseases. Tanzania is a very safe and peaceful country. Recommended for an introduction to Africa. The people are charming and the land is magical. 2. Zambia---just avoid democratic republic of congo border. 3. Swaziland 4. Ethiopia (Ethiopia has recovered well from its harrowing past and is a land of beauty and enchantment) but stay away from the Eritrean border.

All above just for your reference only!