Oh boy, where to start. Overall the video was pretty decent, it had some good information and wasn't hurr durr die cis scum.
What I didn't like was how she bent the truth in order to fit it into her own agenda. At 9:30 she describes how Peach was replaced with Toad in New Super Mario Wii in order to put her back into her place as a damsel in distress. This is only half true. Peach was replaced, but the reason for doing so was because her dress would have been too difficult to animate.
I built my PC last year with a budget of $600. Though, I did salvage my HDD, mouse, keyboard, and DVD drive from my old PC. It was the second PC I've ever built and I think I did quite well, I can play most games at 50-60fps at 1080p on high settings.
The best thing you can do is just read. What I did was lurk on places like /r/buildapc while spending about two weeks on pcpartpicker assembling different builds, I tried to get every last cent out of my budget without going over. It was actually very fun assembling so many different combinations of PC hardware, I learned a lot while doing so. I think buying a pre-made PC not only costs you a lot more, but it actually takes a lot of the joy out of owning a PC.
Sound in general is good enough as it is. What needs innovation is dynamic voice acting.
You'll hear game reviewers gushing over sound in video games when NPC's start changing their speech mid-sentence depending on what they're doing, when things like running and jumping effect what they're saying.
I'd say a PC budget should be around $700-$1600. If you aren't spending at least $700 when building a completely new system then it's not really worth it and you should just wait a little longer until you have enough. Once you have enough you can pick out parts with surgical precision for your exact price point. If it's over $1500 then you're probably throwing money away and not being very cost-effective.