50ft lengths of speaker cables,suggestions?

Building a home, need recommendations on speaker cable, not the best(cost effective), to run approximately 50 foot to equipment room. The sheet rock is already up so this will be fun. My wife is not keen on placing speakers in the family room again, so I need to be carefull-I have not picked speakers yet. My old system was ML Prodigy's and I am also looking at B&W 800D's. So, I am not sure the wife will consider mono-blocks next to the speakers. Thanks,