In my opinion, (for what it's worth), if your children/grandchildren want to play games, buy them a Playstation or X-Box.
I do agree with your above statement as I used to own a PlayStation 2 but even though they are easier to get your head round them as all you have to do is switch them on and insert the game CD and away you go, I still prefer my PC for gaming as the graphics are VASTLY superior in my opinion.
I think this is because you are looking at the game's graphics through the limited resolution of a tv set as opposed to a monitor.
Also a PC runs at much higher clock speeds than consoles and they have the latest 'cutting edge technology' graphics cards like the X800 XT for example.
Finally a PC is upgradeable where as consoles are not.