Dedicated Line

I'm in the process of switching from a Redbook only system to one that will incorporate SACD and PC Audio and I thought this would be an ideal time to install a dedicated line. I have a headphone system that consists of:

-Esoteric K-01 Player/DAC
-SinglePower SDS-XLR Headphone Amp
-Custom PC from EndPCNoise (USB to the Esoteric)

But I'm relatively ignorant about PC Audio as well as dedicated lines. My biggest questions are:

1. Is it necessary/useful to have 3 Dedicated lines for player, amp, and PC? Or would it be fine to put, eg, the PC on a house line since all it will be doing is sending the audio to the external DAC?

2. Is 10-Gauge an improvement, sonically, over 12-Gauge? Most of the audiophile 10-Gauge AC cables out there (Acrolink, Furutech, Oyaide, etc.) are extremely expensive, sometimes $20-$30 a foot, and my box is approximately 60 feet from my system.

3. Related to the above, would it be worth it/possible to install another circuit in my listening room and run a separate AC line to it? That would make it much, much cheaper to invest in the AC cables from Acrolink et al. What would I need?

4. I've heard it's best to put the system on the same "phase" as the circuit; what does this mean?

Any other recommendations/advice is welcomed. I've read through many of the "dedicated line" threads but I'm still a bit confused about everything.
For my system, which is computer-based, I have a dedicated 12 gauge line powering the DAC and power amp only. It's regular Romex wire, nothing special.
The computer itself and the external hard drive are powered from a separate circuit, but not a dedicated one.
This significantly improved my system relative to the previous setup, without a dedicated line. Now I don't use a power conditioner anymore and the improved dynamics are delicious.
As far as the phase question, if more then one dedicated circuit is used, it's recommended that all of them should draw from the same rail in the breaker box. This will bring them "in phase".
Best way to go is separate dedicated lines for digital and analog equipment.
Definitely for a home computer.... They put filthy hash back out on the AC line.

Dedicated lines decouple the power supplies from one another.

Digital equipment switching power supplies put a lot of hash back out on the AC line in the form of odd harmonics an AC transients.

Take two dedicated branch circuits that are ,say, 50ft long each. Because of the impedance of the wire the switching power supply transient spikes will dissipate very fast in the branch circuit conductor on its way back to the electrical panel. Even a lot of the odd harmonics will end up out at the utility power transformer and be dissipated in the secondary winding in the form of heat. Not all....

If both digital and analog are fed from the same duplex receptacle from the same branch circuit the two power supplies are basically coupled together.

Good power cords on digital equipment that shield RFI/EMI can help from the hash coupling to the analog equipment.

A Sub panel can be fine provided the branch circuits fed from them are not too short.
If your computer has an optical output, using that to your DAC could eliminate the need for a separate line for the computer, as there's no electrical connection through optical.
If your computer has an optical output, using that to your DAC could eliminate the need for a separate line for the computer, as there's no electrical connection through optical.
02-19-12: Kbarkamian
The non linear switching power supply of the computer is still connected electrically by its power cord to the power supplies of other audio equipment connected to the same common branch circuit.