Khartoum
I think its very safe - the people are very friendly and you will be far safer there than in parts of London or Johannesburg. Try and get to the Souk and the Nubian wrestling/sword dancing on Friday evenings - the Hilton entertainment is not exactly riveting and the decor is very seventies, but the food in the lobby cafe is hot, fresh and tasty. Bottled water is expensive but don't touch anything else. There are literally hundreds of kiosks to stock up from (don't buy at hotel - very expensive). Hilton only takes cash or DINERS CLUB (sanctions etc).