well... what sort of food do you like?
I've been in SA on and off for about 5 months now... and am a steak lover, currently my 2 favourite places for steak are:
Joops ("yurps") - family run, was voted best steak house in SA for a few years...

and Butcher Boys (in Umhlanga where I stay)

We took the clients (all told there was just over 30 of us!) to a restaurant on Durban beach front (next to the Ushaka marine park) that was called Moyo, pretty good with plenty of African culture.

Couple of people have tried the Cargo hold (again in Ushaka) which is more of a dining experience as it's in a "ship" and you can see the sharks etc swimming in a giant tank...