Speaker wire
Yes, Oxygen free does indicate higher quality copper which is desirable for speaker wires, but don't get carried away with monster cables or anything exotic.
All you need is good quality 14 AWG or 12 AWG copper.
If you want an inwall type installation bulk Belden speaker wire from Westlake Electronic is a good option.
For around the room, another option is a spool of Sound King speaker wire from parts express. Note that it is "oxygen free".