The 6600k is useless for you, forget about it. You're not overclocking, so the 6600k is a waste. The i7-6700 is the same chip as the i5-6500. The i5 just has hyperthreading disabled and a lower clock speed. So, yes, the i7-6700 is better than the i5-6500, but whether it's worth the price increase, is debatable. If you're not utilising all of the threads with the i7, it's pretty much wasted money. An i5-6500 is more than enough for streaming, since streaming relies on your internet connection mostly. It's not necessary, but even an RX 460 would be a nice addition. GPUs can help with editing/rendering and what not, if you do any of that. Plus, even if you have an entry level GPU, you can do a little bit of gaming on the system, if you decide to do so at any point. An RX 460 or something similar wouldn't go amiss, but it's not necessary.