In article , "John Borman"
says...
snip
That's given me even more to think about. I'm a bit confused by this Cat 5
cabling, what items can it be used for, surely if its just for computers as
I thought then you would only want it in say an office and maybe bedrooms.

You can use it for telephone, home automation and anything else that
uses low-voltage low-current.

As someone has mentioned what's the need of running two Cat5 cables to each
point? and will there be a central point, say a cabling cupboard where you
could have a broadband modem then have the cables running from this point to
all the rooms where the cable terminates (Would that require a router)

Yes. Doubling up on cables gives you a spare in case there are
problems with one of them (it's much easier to run extra cables in a
new build than it is to replace them later, and the extra cost is
negligible compared to the hassle) and it gives you the opportunity
to use the spare as above.