Do not use cat5 wiring. Yes it will transmit the sound but the wires gage is too small.
It is also solid core wiring. Solidcore wiring is not the best for speakers.
Use a good quality oxygen free copper speaker cable around 16 gage up to 50 ft.
If you have 100 watts/channel or more you should use a 14 gage wire. If you are over 150watts/channel use 12 gage. Remember the wire gets bigger as the gage goes lower.12 gage wire is thicker then 18 gage wire.
I personally like the Moster XP brand of speaker cable. it is not that expensive. Sometimes moster cable can be overpriced but not so much in the case of this wire.
It is very flexible and will layout nice on the floor. I have purchased wire in the past that was similarly priced and it was garbage.
The 20% rule stated above is indeed whack as I would have been spending $2,400 on speaker cables. NOT GONNA HAPPEN.
About a $1 to $2 per foot is resonable. You will get a more than adequate wire for that price. That is about what the Monster XP cable I use costs. But copper is expensive now so the cost may be higher.
( MEATSNAKE Richard Hammond, Wed 28 Aug 2013, 15:40, 2 replies, latest was 12 years ago)

12 gauge is a shotgun.

( the mighty badger Aphrodite, on a bar stool, by your side, Wed 28 Aug 2013, 15:42, Reply)

You need a spool of in-wall rated 12 ga, or 4-conductor 16 ga wire. Try www.partsexpress.com.

You want a CL2 or CL3 rating as this is fire-code in many areas.

Do NOT spend $$$ for high-end copper. Good oxygen free wire is all you need for movie soundtracks and the 12 ga will work fine for the long runs.

Run the wires zig-zag between the studs with insulated staples pounded in half-way. If you ever need slack in the future - tug to pop the first staple.

Run the wires through plastic electrical outlet box's. Pull enough wire to create a un-broken run from the amp to the speakers. Later you can install Decora wall-plates with binding posts, but to start - just buy blank wall-plates and drill holes to thread the wires through. This is cheaper, simpler and frankly better than binding-posts in wall plates.

Run CATV coax to the corner of the 2 longest un-broken walls. This will be your subwoofer cable.

Run Cat-6 network cable to behind where your rack is. You can install a small $49 switch to send internet to your devices. Wireless is fine - but wired is faster and better.

Run telephone wire to behind where your rack is. Cable and Sat box's often want this so you can order pay-per-view movies and shows.

Label, label, LABEL:

Go to Radio Shack and get some of those Wire Labels with the clear tape that wraps around the white label. Do a simple "A", "B", "C" label on both ends of the wire. Repeat the labels every foot or so as the wires emerge from the walls and a foot or two into the walls (in case you tug to pull slack).

OPTIONAL:

At the back of the room - put an AC outlet on the ceiling for a projector. You can run a long HDMI cable up there or run some plastic conduit with a fish-rope to pull a cable through later. Try www.bluejeanscables.com for good, long HDMI cables that will survive the trip.

This is cheap to do now - expensive to do later.

Hope this helps.
( MEATSNAKE Richard Hammond, Wed 28 Aug 2013, 15:43, Reply)

I dunno mate, I use Van Damme Studio Grade.

( the mighty badger Aphrodite, on a bar stool, by your side, Wed 28 Aug 2013, 15:48, Reply)

I bet that splits easily

( hartley hare Just some prick who thinks it doesn't apply to him, Wed 28 Aug 2013, 15:50, Reply)

I just use 2 core mains cable

( Peej, Wed 28 Aug 2013, 15:42, Reply)