Dedicated 20 amp circuit. 10/2 or 10/3?

Ok. So each dedicated circuit should have 10/2. 
I watched ps audio run 10/3 and said they were doing a double ground?

I plan on running a dedicated circuit for each device. Amps, preamps, subs, etc. 

That's my other question.  Which side of the panel should I use? And should I place all my dedicated circuits on the same side?

Ok. I installed my dedicated 20 amp circuit using 10awg romex. All is good!

I will install 3 more dedicated circuits for subs and accessories next.