There are lots of Game Reserves opening up in the Cape now so there is a good selection to choose from. One that I can recommend is the Garden Route Game Lodge (http://www.gardenroutegamelodge.com/). It is a 3 hour drive from Cape Town up the very beautiful Garden Route. We saw elephants, cheetah, rhino, lions and lots of other wildlife. The service and accommodation was outstanding - if you aren't going to go north (where the game reserves have maleria, etc), then this is a good option. Another option to consider which is only a 2 hour drive from Cape Town is Aquila Private Game Reserve near Worcester (http://www.aquilasafari.com/) over 10 years ago
I agree with Safariguy - the best places to see wildlife is in Kenya.
I camped in the Serengeti and the nogorongora crater. The amount of wildlife was from far the best i had seen. There was nothing better then to see a lion take down a kill right in front of you. Something you may never see if your life.
The masai mara is amazing! A must see for sure.
Enjoy and be safe! Don't keep food in your tent if you are camping - the wild pigs will come and raid your tent for the food even if you are in it!!! about 10 years ago
If you are up for the trip then the best place in South Africa for wildlife is by far the Kruger National Park!
I was there in March and saw lions, elephants, giraffe, cheetah, rhino, crocodile, leopards and much more!!
From Cape Town its a 2 hour flight to Johannesburg, and then from there you can fly on a small plane to the park, or it's a 5 hour drive..
highly recommended and deffinately worth the trek!
(You can also see Blyde River Canyon on the way from Jo'burg-the 3rd biggest canyon in the world!)
The pic for my profile was taken there! about 10 years ago