If the main purpose or goal is to play games most people will choose the console because its easy to setup with your home theater system. Its very plug and play.
However if you are an avid FPS or RTS gamer than you will obviously buy a pc.
two different groups of people . PC's are for people who have money and are not afraid of technology.
Consoles are for people who are afraid to get dirty.
You go to a store and see a PS3 next to a computer. You are there to buy some form of entertainment, what will u buy?
price tag 600 vs 1500.
In theory most people will buy the PS3 because its cheaper. However those that like technology and are curious buy the pc because it can do alot more than a ps3 can.
Also keep in mind that in reality a console is not cheaper at all. To use a console you need a high def television (ps3 or 360) that will set you back at least 500 dollars for a 24 inch ... but why if u want high deff get a 40 inch... thats another $500 +
Oh right, you want better sound ... $500
Oh yeah! your buddy wants to play with you! ... $40 per person (controller)
Oh wait .. I have to buy all my games from a store! Costs of discs are more expensive than downloading games off the internet. (thank you steam)
All in all you end up spending more money on a console then you do for a pc. It is just easier to spend less money at one time.
Oh yeah, the console graphics cant be updated ... shux
Just my two cents