Making my PC like a console...er sort of

So I've search the best I could and came up with no conclusion, so I apologize if this is like spam.

My question is what would a PC hardware spec have to be to be comparable if not better than PS3 Or Xbox. If my question isn't clear allow me to elaborate; I'm sick of having to upgrade my pc every year just to play a new game mean while the ps3/xbox requires no hardware upgrades at all. I realize/ assume it is because the game's software are optimize to run on console and that some developers like Activision simply ports it over to PC get wring out a few more dollars out of people.

I know building a PC that is upgrade proof is unreal. PS3 seriously needs to support mouse and keyboard in-game!