Capacitance: Help me understand

It's all relative. One farad is high capacitance, but not as high as ten farads and should be relatively inconsequential at audio frequencies. A few picofarads per foot is very low in comparison to either. If any decent audio cable really affects the tonal balance, it is probably more a matter of the electronics design; that is, circuit performance susceptible to minor load characteristic changes. I know this is not a popular position with all, but there...I sadi it. :)

Please let me clear up one small item in my post above. I knew that a vacuum was a better dielectric than air, but assumed that no vacuum interconnects existed. I was wrong. I saw an ad last night in Stereophile for "the worlds first vacuum interconnect." Who would have imagined?
I also don't think that "ANY interconnect that uses a foil shield is a high capacitance design." If enough space is left between the center conductor and the shield, it can be low capacitance.
I was curious about the Wireworlds, so I went to their website, but they don't post the electrical specs of their cables.
I agree with Sean that cables can affect the tonal balance of a system and that it is system dependent. I based my speaker placement theory on the description from Ignatz that he had "a too deep soundstsage with diminished volume from the center image."
Ignatz, I have some very low capacitance single ended homebrew cables that I would be happy to let you try. Send your address to me and I'll mail them to you. Also, what length do you need?

Thanks to everyone for your responses. I continue to be impressed by the amount of information available on this forum.I now think I have a general understanding of capacitance, which leads me to a further question. Wouldn't the effect of a high capacitance cable on sound have a lot to do with the output impedance of the preamp and the relationship between output impedance of the preamp and input impedance of the amp? Thinking of the pipe example wouldn't a preamp with a realtively low "push" coupled with an amp that has relatively high resistaqnce to that push exacerbate capacitance problems w/ a cable?

Although I'll probably be trashed by other engineers, I think it all has to do with the speed of electrons.

Capacitance slows them down. (Remember EE-101: voltage can't chage instantaneously through a capacitor.) Ideally you to want them to move as close to the speed o' light as possible. I think this explains why silver conductors have a distinctive sound; ie, great transients & realism.

Well this EE would like to point out that it's not the electrons that move through the cable at all - it's charge or electromagnetic flux. It is very similar to the way sound waves travel through the air. The air molecules do not move from the source to your ear they instead impart their momentum to the particle next them and so on and so on. The speed at which a charge moves through a cable is termed the propagation delay. Like sound, the speed of propagation changes depending on the material it is being propagated through. In a copper cable the speed of propagation is roughly 2/3 times the speed of light. - Dan