Best speaker cables for longer runs


I realize people like to keep their speaker cables short, but a redesign of my rack placement may necessitate runs of 20 feet or more. Any particular brands work well under such circumstances?

I have a theta dreadnaught ii and b&w 802d. Cost may be an issue as price does mount up.
diw
Post removed 
Tvad,

I once had a certified NSF technician come to my house to calibrate my rear projection HDTV. He was not an "audio guy". He looked at my anti-cable speaker cable and asked me if it was some sort of modern art, before I told him that those red wires sticking up in the air were speaker cables. After he stared at me for a second, he shrugged his shoulders and went to work. 20 feet of red wire! I gotta see this!