Power Conditioners

Tom - You do realize that there already are filters inside of almost every audio device? Other thing, what you want in electron flow is being delved into under the heading of superconductivity, maybe one day.

Depends on what is meant by current limiting. In fuse/circuit breaker lingo that means the protection device will trip out before current can reach it's maximum when you have a low resistance short circuit, this is a good thing & has no inherent drawback, it cuts down on the potential equipment damage and arc flash hazard if something goes very wrong.
If you mean current limiting in the sense that a power conditioner can not feed your equipment with all the power it wants on a loud passage, then you will lose some dynamic range especially on the low frequencies.

Stenho - Some of the line conditioners and probably a higher percentage of the devices sold as ac filters work by shunting noise line to line. I.E., no current limitations, you can actually end up with a more robust current supply with caps hooked up close to the load or good ac filters close to the noise sources.