Low capacitance; a good shielding scheme; and solid connectors are paramount to a good interconnect. The pf rating per foot is not as important as the total pf; i.e., the length of the cable plus the capacitance of the connectors. A typical 2'-3' length should pose very little difference in frequency response whether you choose bluejeans' Belden wire or their Canare wire. I used to use a Cardas interconnect that had a pf rating twice that of Canare LV-77S, and it worked just fine. Only thing was, that I sold them and used the money to cable my whole system from bluejeans- with no degredation in sound quality whatsoever. None.
With speaker wire, the capacitance issue is a little less important, especially with reasonable runs. Resistance and inductance play a bigger role. The expensive stuff may use a complex design to minimize resistance without having to use wire the size of battery cable; but in general, unless you have your speakers more than 50' from your amplifier, it doesn't matter much. I use Cobalt 10 ga. Ultimate speaker wires. Why? Well, I wanted to move my equipment rack off to the side and out from between my speakers; which meant I needed around 16-17'. The 10 ga. is heavier than I needed (it looks like black garden hose

), but the quality of the terminations is excellent and the price was right. Prior to that, I used Audioquest Type 4. Sound wise- even if I strain- I can hear no difference.
By the way, for all you cable afficionado's out there, my hearing was just checked- and despite hearing a bit less below 60 hz in my left ear vs. my right; my hearing is fine. Not 'Golden', but fine.
(btw, Kevin @ DIYCable has some killer deals on wire as well. But it would be hard to beat bluejeans for real value)
my 2 cents,
WEEZ