Alec Meer of Rock Paper Shotgun has posted detailed instructions and advice on building a gaming PC that meets and/or exceeds the newly announced PS4 and XBox One, for approximately the same price.
Obviously you can’t build your own Xbox One or PlayStation 4 – they use some custom hardware not available to PC-builders to do their next-generation thing, they’re running bespoke operating systems (and all the horror-DRM that goes with it) and contain it all with in a comparatively small black monolith that sits underneath your TV. Additionally, console games can be made to specific hardware requirements, which can entail a far great degree of optimisation than trying to target a hundred thousand million different PC configs. No matter what the console generation, the PC comparison can never be an exact one. What you can do, though, is build yourself a PC that has a little more grunt under the hood than these apparent future-machines, for pretty much the same amount of money.
Be sure to read the whole article for some great pointers on building a “future-proof” but reasonably priced gaming PC.