Necuno
The Piper
Simple answer...Avoid the i7 2600 and 2600K and get a i5 2500k.
They perform exactly the same in games, its only once you get into video editing and encoding that the i7 pulls ahead.
Considering that the i5 2500K is roughly a R1000 cheaper and offers the exact same real world gaming performance, sometimes even a little bit better than its big brother. its really a no brainer... Buy a i5 2500K.
Edit: Also I can confirm that the 2500K runs as fast as its big brother. I have 3 i5 2500K rigs and 2 i7 2600K rigs xD While gaming I can't see a difference between any of them.
Unless of course you'd be doing more than *just* gaming