Most common subwoofer input?

I just bought a new house and I plan the build a 5.1 system in my family room. When I talk to my builder today, he suggests me to build a in-wall stereo cable for my rear speakers and subwoofer, so there will be no cable running around my family room. I know that rear speakers use normal speaker cable, however subwoofer have so many different type of input, such as: RCA, speaker wire, phono input or Neutrik Speakon. Which type of input is most common use for sub?
thx.