Having used a lot of manufacturers interconnects and cables over the last few decades, one product stands out for me. Inakustic cables (and their remarkable AC conditioner) are the finest I have heard.
Perhaps not the highest profile in North America they are a major concern in Europe. Have a look at their website to see their professionalism and wide range of products.
Aside from sound quality I believe these are unique in their method of construction and offer huge value for what goes into their manufacturer.
I use the 4004 air speaker cable and 1204 interconnects and could not be more pleased.
The 3500 Power conditioner is again, the best I have used and I would consider it an essential starting point for any serious system. It is one of those components that I would never consider replacing in my system.