the only reason to get a "K" version is to overclock. there is literally no other difference beween the regular and the "k" version
however, it is worth noting that 3D rendering will benefit directly from overclocking your CPU. so unless you're planning to get 5+ years of work out of that CPU, I would just get the "K" version and put a reasonable overclock on it. it should be fine for at least 2-3 years, and chances are it'll make it to 4+ years of service
the "K" version doesn't have extra graphics, it has the sample graphics as the regular i7 3770. neither of which are particularly good. again, the i7 3770 and the i7 3770K are EXACTLY THE SAME, except that the 3770K has an unlocked multiplier that can be used for overclocking.
1. a fairly large amount of content creation work is still done on the CPU, it's not all done on the GPU. at one point in history, the CPU did all the work, as graphics cards got better, people slowly started offloading more and more tasks to them.
2. overclocking, if done correctly, is like free extra performance, a 3770k should be able to overclock to 4.2Ghz safely, which give you at least 300MHz of free performance.
3. if you really don't want to do this, then just get the i7 3770 version. again, architecturally, the two chips are the same.