Some people have been asking about malaria-free safari options, so I thought it would be useful to add a thread about them to the Africa board.
If you want a malaria-free safari, you'll need to stay within South Africa as the reserves in other countries are malarial. In terms of game-viewing, I'd recommend the reserves in the Eastern Cape (near Port Elizabeth, so conveniently located for people who are driving the Garden Route from Cape Town). There are some large reserves in the area with a high land-to-guest ratio (providing an exclusive safari experience) which offer the chance to see all of the 'Big Five' (lion, leopard, rhino, elephant, and buffalo). My top recommendation in this area would be Kwandwe, which has two lovely lodges (classic safari-style Great Fish River and funky modern Ecca) as well as two villas. In addition to great game-viewing, Kwandwe offers the opportunity to learn a bit about the area's history. Another very nice reserve in this area is Samara, which is known for its cheetah conservation programme and excellent sightings of these cats (which are not commonly seen in Southern Africa compared to East Africa). Watching a cheetah at full stretch chasing down an antelope is an amazing sight.
Another malaria-free option is Madikwe Game Reserve in the Northern Province. Madikwe is a relatively young reserve which is a great conservation success story, as it has been converted from derelict farmland into a wilderness area. This process is still ongoing, so you may occasionally see remains of the farms which formerly made up the area. All lodges can traverse over the entire reserve, which makes game-viewing less exclusive (though they do try to coordinate to avoid too many vehicles at one sighting) -- the only exception to this is Makanyane which has a small private area in one corner of the reserve. The game-viewing here can be uneven (sometimes you'll see a lot in a day -- other times you can go days without seeing much) as the animal density isn't as high as in more well-established reserves, though they are working on it. LL frequently has packages featuring lodges at Madikwe such as Tuningi and Mateya (the most luxurious option at Madikwe). Another excellent option is Madikwe Safari Lodge, which is run by AndBeyond (formerly CCAfrica) and has superb guides.