Home Theater Cable 5.1 speaker cable important at 5.1 system? what u use all ? can u advise me plz need like 40 feet suuround total and 15 feet front
It isn't going to make enough difference between the cheap home store brand on a roll and high quality wire that you can hear the difference. I would recommend 16 gauge (16AWG) or 14 gauge (14AWG) wire for front and rear. Wire off eBay is hit and miss - sometimes OK and sometimes junk with oxidized copper or cheap sticky plastic insulation. The standard home store brands are fine as is the "zip cord" / lamp wire which is sold by the foot unless you are doing in-wall wires which require special in-wall rated wire:
What I use in my system is Belden 5000 series Cable - the 12AWG would be fine and can be purchased at Blue Jeans Cables by the foot as well as screw on spades, bananas or locking bananas. These can also be welded to the wire if you select the wire lengths and pay a little extra.