I work in computer retail and strangely enough I am not one of those guys that feels the need to recommend a GTX680 to someone because I am greedy - I offer the sweet spot because not just anyone is going to drop R14000 on a graphics card. Mid range is where it is at, you will get good value for a fraction of the price.
Of course, you don't want to get cheap components either - rather spend a little bit of extra dosh on something quality - mid range as well! Some people say R15k for a gaming machine, you can get something going for even cheaper, in the R12k range even.