Long speaker wire runs

Hi everyone;

I am setting up a new home theater. For my audio, I have an Anthem Statement D2 preamp with the matching P2 amp. For speakers, I have B&W 802D's , HTM2's and 4 SCM's. The speakers are about 20 feet from the equipment and with in wall wiring, will require approximately 40 feet of wire. What is a viable option for in wall wiring with this distance for all the speakers?
Look forward to hearing your suggestions.