On Wed, 15 Feb 2012 12:42:12 +0000, The Natural Philosopher wrote:

You can, but its not low enough resistance for decent bass.

(Cat5 as speaker cable)

True enough but not an issue with most domestic home cinema systems
where the "sub woofer" also handles the LF from the other five
channels via "bass management". This avoids the requirement of trying
to place 5 full range (ie large) speaker boxes in the room.

As for the OP it's probably easier to buy an AV Amp of some sort to
stick in the pile of black boxes and everything goes through that.
All the telly needs is a single HDMI and mains. No interest in
broadcast telly so there isn't a requirement to get an audio signal
back from the telly's reciever(s) to the AV amp. Some hint of DSAT
but that would go through the AV Amp...

I'd be wary of mounting a TV up on a wall, too easy to get it too
high and a crick in the neck watching it.

Cabling position really depends on the layout of the room and
location of the viewing listening position. Each corner wouldn't
really be very good if the listening position screen line is on a
diagonal of the room for instance.

--
Cheers
Dave.