As someone who grew up in Durban I can tell you that it is a great place to take your family on holiday. Some amazignly beautiful beaches. You have the Durban beachfront which has been extensively improved since the Soccer World Cup. uShaka Marine World is a great day out. If it's shopping you want, Gateway and Pavilion offer you plenty. The South Coast and North Coast have some utterly stunning beaches if you want to travel an hour or two. If you feel like a few days in the mountains the Drakensberg is about a 3 hour drive. You have game parks a few hours away as well, but I think that can get quite expensive.
Cape Town is still the number 1 tourist destination in SA, but you can't go wrong in Durban, especially around Comrades time. The weather in Durban in winter is also something to appreciate. I can just about guarantee you that everyday will be about 22 - 26 degrees with hardly a cloud in the sky. Cape Town will most likely be wet and windy in winter. Obviously there is a crime element to be concerned about though, but if you don't take unnecessary risks like sitting around in parked cars in lonely areas, or walk along the beachfront too late at night, you should be ok.
SD - I have downloaded the latest MT episode so I'll listen out for your name check. It'll be the second one I would have heard in having only listened to a few episodes. Your 9.9 (IIRC) for Comrades this year was a great story. Epic effort at the weekend. 4 marathons in 4 days is surely an indicator that your best Comrades yet lies ahead.
Edited: 02/11/2012 at 13:19