I was going to chase is all my leads when I did my install. Like you you never know what you are going to buy in the future so I mounted my TV on a floating wall which was about one and a half inches from the wall surafce and all my wires and cables went behind.
I currently run a Windows Media Server, a Laserdisc Player, HD DVD Player , Two Amps, SkyHD and a Standard Pioneer DVD player. All these are housed in a cabinet next to my TV and as you would guess the wires are plentlyful. Anyway here is some pics of what I did rather than Putting wires in the wall.
The pics were taken about 1 year ago and it is easy for me to add wires (just have for Sky HD) If putting wires in the wall be careful to leave enough slack as if you ever get a new tv in the future the inputs might be located differently on the back panel
I would go for a standalone option every time but as you have a PS3 might not be worth your while.
Tv on wall with no floting wall and nothing in cabinet connected
Cut the ply to fit the chimney breast
Added batton for the ply to sit on
Tested on the wall before adding wires
Added all wires and speaker brackets
Wired up all my cabinet
All finished nice and tidy
My TV is 40" but I am looking at a 50 in a couple of weeks and going to get my Panny Projector out again and do a BIG screen install but...... thats another story..
Scotty