You make some good points, however for the extra money you will spend on a decent self build.........for game playing I would buy the console. As the original post said game playing I have orientated my suggestion towards just that.
If you are still intent on purchasing a PC send me a PM and I will help you spec it, be aware in advance however that starting from scratch (I mean case, psu, everything) you are (fact) going to spend considerably more than you would should you choose a console.
Nope, I don't work for Game, I don't programme (anymore), and to be honest, I don't spend that much time playing games..........I don't have any spare time
Good luck with your decision.
Fanum, to answer your points specifically,
Can't comment on the multiplayer element as I only ever play(ed) the game(s) in single player mode.........like I said, don't have a great deal of time.
Poor processing power : Errrm not for gaming they don't.
Poor resolution : for periodic game play my 42" LCD screen via hdmi is just fine.
Expensive games : you could be on to something, however I get so little gameplay time I get all my games way way way after they are chart titles so considerably cheaper than full price.
Unreliable : my PS3 hasn't missed a single beat (cursed it now though
)