Well now, you'd need a 2nd pc for streaming purposes, with it's own dedicated internet connection (you can get cable for that, BT for gaming pc!).
External Capture card with audio mixer, specialists audio equipment for music producers ie sound card/professional microphone/HD camera etc. Mmmm, maybe throw in some fancy live video editting with some Avid production hardware, think how a TV studio would operate / render clips for live TV... maybe a 3rd dedicated PC/Mac for that.
Hmm, then a network storage facility, so a 4th setup which is a big Harddrive cache, since of course you'll want to download the entire internet at some point.
More specialist sound speakers, perhaps outsourcing help from specialist inhouse cinema company to set up a fantastic speaker system.
Last but not least, an identical 5th gaming PC with mirrored drives just incase you get a problem, you can hop into the other one.
Hmm, small additions such as a quality gaming chair, glasses, 3d glasses, 3d monitors, bungees... hmmm..
Also, perhaps contact IBM to see if they'll build you a Supercomputer for a modest fee.