I'd go with the custom cable as they have the technical data to prove their cables can handle the 35 Mhz max frequency of HD signals. In truth - the cables from target/best buy MAY actually be built with good coax that can handle HD video for 10-15 feet. But the custom cables use coax tested...
The coaxial-digital cable is simply any video cable (This is what the designers of the SPDIF format had in mind: a 75 ohm video cable). So a inexpensive Radio Shack or AR Pro video cable should work fine. Component Cable: Here you have some choices. But first: are you running standard...