Note on cables

I don't want to write too much about them. It's a Pandoras box.  I am a believer that cables are audibly different. I LOVE exotic cables.
But be careful.
I think that circuit topology is 10 times more important than cables, and system positioning in room is 10 times more important than cables. And choice of system elements (amps, sources) is 10 times more important.
People attach FAR TOO MUCH importance to cables. So many people end up spending 500 dollars on an amp and same amount on IC and speaker cables but later, trying in vain to improve the cheap amp sound by Siltech wires.
I can guarantee that if I wire all my system EVERYWHERE with cheapest zip cord, it will still thrash all and any systems out there costing 10 times  as much, systems whose cables cost more than my entire system. Because I have well thought out system.

From my experience, in cables the sound quality is a result of:
33% conductor material
33% insulation
and 33% geometry
One percent are plugs and termination.

Some warnings:

1. AC cables: read elsewhere in HERESY section.

Remember that the cable BEFORE your amp , in your wall, goes anything between 100 to 1000 m to the street transformer. And it is just plain copper wire.
After your "python AC" cable goes ... 100 m of hair-thin copper motor wire in the power transformer of the amp. The contribution of your AC cable - "as a cable"- to the electrical performance is ZERO.
Very audible are AC filters, usually consisting of 0,01 uF cap in parallel and a ferrite ring. This RLC component in AC supply is important. It can be BUILT IN some of the exotic cables. So remember, these RLC components are worth less than a dollar. They are usually hidden inside plugs.  Or they form a "cigarette box swallowed by a snake" kind of addition to a cable. It is just like my filter described elsewhere.

I experimented by adding a resistor to the AC cable in series. I mean a resistance difference between a thin AC cable and exotic python is like between 0,5 ohm and 0,01 ohm.
I added R values from 2 Ohm to 50 (fifty!) ohm and there was absolutely no audible difference in the amplifier's sound. So thickness (cross section) of even power amp cables is irrelevant. Just more irrelevant is AC cable cross-section for CD players and other sources.

2. Speaker cables.

Remember, that inside your speaker there is usually the lo-pass coil made of 50 meters of 1 mm motor wire. Plus some 3-4 m of internal zip cord wiring from XO to speakers. And inside drivers there is many meters of motor copper coil wire. So 2 m of speaker wire is not that important.  Don't over-estimate its significance unless the whole circuit is wired intelligently. Investment in exotica silver will bring small returns unless you plan everything well. I advise bi or better tri-wiring the speakers with dedicated cables to each section. In this case the cables can be really cheap and thin. I myself sold all my super cables and currently I run on wires costing less than 10 dollars in total of my whole system.

I normally laugh out loud about people who  define their problem like this: "Oh uh I have these great speakers but I thing they may be a little bright in the trebles so I am gonna go and buy the mellow sounding Van Den Hul carbon speaker cables maybe this will tame the brightness a little bit"
OOooppps there goes 2 K Euros.
My recommendation is to buy 20 euro-cent 1 Ohm 1 watt resistors and add to the goddamned tweeters and spend the rest of money on a 2 week stay in Croatia for the whole family. Or better - 18 inch woofers.
And by all means - DO biwire and triwire if you can, using different dedicated cables for all circuits - never believe in a doctrine that says: same speaker cables for biwiring for whatever claim of "coherency" That's B.S.

3. Interconnect cables

These can be very audibly different, but don't forget that inside your amp or pre amp there is probably 1 meter more of hookup wire, usually cheap one, or even worse - a hard disk type of ribbon or something like that.  Audionote sells fabulously sounding and criminally expenceive cables but inside my old preamp M2 I found half metre of hard disk ribbon. 
Rewire everything throughout, inside out, with just decent cable, instead of blowing a grand on an IC alone.
By definition XLR balanced IC's are much less sensitive to quality issue than RCA's.
Having said that I just adore the way the Audio Note AN-Z sound in my system. (used to sound because I sold them).

4. Digital cables

As explained in Transport section and in MYTHS section - these are just analog cables which do transmit frequencies above audio - usually in the 2 to 20 MHz range.