Dedicated Line(s), One Line or Two?


We are renovating our NYC condo (in a 1960, 175 apartment building) and using it as an opportunity to run a dedicated line direct from the breaker box to the two-channel system (20 amp, 12 gauge wire).  The contractor ran the line (singular) as requested.  But now I'm reading that ideally we should have two dedicated lines, one for the digital source (CDP) and one for the analog components.  The problem is that running the one line took a lot of work, chopping wall channels, removing molding, etc., and the new line has already been closed in.  I could have it redone to add a second line, but it won't be easy or cheap.  (Obviously I should have done more homework sooner.)   Questions: How much "dedicated line" benefit am I giving up if I just stick with one line, and have two duplex outlets on that one line?   Put differently, having gone to the trouble to add one dedicated line, will I still get enough improvement, so as not to feel like a complete fool for not adding a second line?   Is there a material downside to having digital and analog both drawing power from the same line?  Any input appreciated.  
whitecap
Many thanks for the helpful comments.  As it turns out, there would be just too much tearing out and redoing brand new soffits and walls, etc.  So, I am going to stick with the single dedicated line.  I will explore the various suggestions offered here.  In particular, Terry, thanks for the input about an isolation transformer, will consider it with my electrician.  
I'm in Manhattan as well, and would love to hear your JL subs when your system is done.   I'm trying to decide as well what dedicated lines to install (I'm running off a single 20 amp right now). 
This thread has me thinking.   Since the digital (a dac only in my case) needs so little amperage, why not use the standard wall outlet with a small isolation device or power conditioner for that, essentially giving you two circuits.   I'm going to try that as well.   
Also I use an older ps audio quartet on my elaborate computer editing system (which also runs jriver for my stereo) just to try and keep it from polluting the condo's AC.