The first rule of data cabling is use the state of the art wire. There is
actually something to be said for running smurf tube stub ups into the attic so
you can replace the wire.
Media is the cheapest part of the project.

You should still terminate with cat 5 connectors so you are compatible with the
world.

I am not all that concerned with power cables in a home. There aren't the big
switching transients you see in an office building and lan cards reject 60hz
noise. I wouldn't tywrap them together but if they happen to share a hole now
and then I wouldn't lose my mind. Usually you can just pick another hole for a
cat 5.

The real trick of data wiring is making up the keystones, not running the wire.

Don't strip any more than you have to, don't untwist the wire more than you
have to and do make the leads short in the connector. Usually there is a
picture. Do it.
This is a transmission line, not a door bell.