I am looking to rearrange the lay of my speakers on my Onkyo HT-SR600 system (TX-SR304B). I will need newer longer wires for the surrounds, and have been meaning to upgrade the cheap OEM wires for some time. Looking at several charts, I think I need 16 gauge wire unless this is a little over. the 18 gauge is about half the price

The back surrounds will run about 35'. The fronts about 10'. The sub about 12'.

The 304 sends out a 6 ohms.

accord to this I should use 16 gauge for the back. I could go 14, but I don't want to waste the money. I am looking at the monoprice ones. I guess I could just use the old wire for the froms. Might use the left over for the center, sub and front surrounds in that order with whatever is left from a 100' spoo.

http://www.roger-russell.com/wire/wire.htm

You'll be fine with 16 gauge wire. 35 feet is long and 18 gauge is out of the question at this distance. You're barely makin' it with 16. The 304 is not a very ballzy amp anyway so you're not gonna be puching any serious current anyway so 16 should do.