Cape Town is lovely - if you, like us, have a limited amount of time in South Africa and you want to see as much of the country as you can, then please make sure you leave a decent amount of time to visit Cape Town.
Some great things we did, that I'm sure all the tourists will get to read about:
Cable car up Table mountain - beware though that this is weather dependant and if the winds/clouds close in then you won't be able to go so don't leave it for the last minute!
That said, see if you can get up there with a small picnic (and some warm fleeces) to watch the sun set. That's a great memory!
V&A waterfront - full of tourists and tourist prices, but it's a lovely place to spend an afternoon at a waterside restaurant eating lots of lovely prawns and downing copious quantities of white wine. The police are strict about drink driving so make sure you have a designated driver.
Green Market - again it seems fully set up for tourists and quite a rip off at times, but we did buy some lovely carvings and things there.
Wine Farms - We picked a couple of the big ones, our favourite was Spier. They've got a cheetah there that we had our photo's taken with. Superb wine and food.
However we were lucky to have some friends in Cape Town and they showed us a couple of things that the typical tourist might not get to do:
Camps Bay - Sundowners at La-Med followed by dinner at a wicked seafood restaurant called The Codfather. It's at the end of Camps Bay beach road and I'm sure that if you book you can get seats with a great view of the evening sunset.
Swimming with the penguins at Boulders beach - there are a limited number of people allowed in there each day, and I'm not sure if you have to book. We loved the penguins, they're amazingly tame.
The views from Blouberg - It's the sight that we all know from the postcards - Cape Town city nestled at the bottom of Table Mountain. Get across to Blouberg - again at sunset if you can as the light is just wonderful. We went to a seafood restaurant - I can't remember the name of the restaurant, but any of the ones along the beach road will give a lovely view of the mountain and the city, especially as the lights come on after the sun sets.
Make sure you get there early enough so that you can have a long walk along the beach - the water was too cold for us to swim, but the surfers seemed to like it (I think their long wetsuits with hoodie, booties and gloves may have been a contributing factor).
All in all, you'll need at least a week in Cape Town, there's just so much to see and do!