Dedicated AC Lines??

You definitely need at least two; maybe three dedicated AC lines on their own circuit breakers. Digital equipment should be on it's own circuit.
You should hear a quieter back ground which should provide you with all around better performance.
Example: more dynamic bass, mids, and highs. Wider and deeper sound stage, providing ones equipment is up to the task. Your equipment should be fine.
If you have room in your main panel run the lines from there. If there isn't room for two or three more circuit breakers you will need to run a subpanal box off of your main panel.
Use good AC outlets, my favorite is the Porter Port. See my reviews under user name Lak, and check out my power filtration system under my systems.
Finally MUCH has been written upon this topic, so do a search on the Audiogon forums.
Best regards,

Arch7,
In my opinion good AC outlets do make an improvement in all types of situations, yours included. If I’m incorrect you’re out only about $35 dollars plus shipping per outlet.
Systems I’ve worked on always have improved significantly with dedicated AC lines and circuit breakers, although I’m sure you can find people that will tell you differently in their personal scenario. In your situation, the way you described your set up, I’m sure dedicated lines will make a huge improvement, and should be a first step along with the AC outlet (such as a Porter Port or equivalent).
I can’t explain why there will be an improvement, but I’m confident you will like what you hear. There are others on this site that are qualified to explain the why part, I can’t.
After I added my dedicated AC lines and circuit breakers, the other way I heard another huge improve was with the addition of the Xentech Extreme (5 KVA) isolation transformer. I could live with just the dedicated lines and circuit breakers however I chose not to.
Are there other ways to handle the problem? Sure, some type of power conditioning in conjunction to what you are currently doing, however it’s more of a temporary Band-Aid (in my opinion) then a fix. I’ve tried several products before I installed the dedicated lines and circuit breakers. They did improve the sound however I’m offering for others to learn from my mistakes and take a short cut, including saving some money on their journey to better sound.
New isolation transformers such as a 5 KVA Xentech Extreme are expensive however at times can be found used from an electric contractor or on EBay. The correct isolation transformer can reduce some noise frequencies by (-146 dB). Another good option is a Topaz isolation transformer.
My bottom line is “enjoy the music”.

Arch7,
Good idea trying the Porter Ports and the outlet in another room that has little or no resistance on.
Good point about the “Topaz Isolation Transformers seem to be just plug and play so to speak. They have a standard cord on them and either an outlet or cord coming out. Seems like they can be plugged into an existing outlet rather than being hard wired at the panel.”
Just be cautious regarding the audible hum of 60 dB which might be annoying if they are located in the same room as the music. Also make sure that what ever equipment you plug into it won’t bottom out the transformer, in other words the KVA number is important.

Zargon,
Good advice given.
Guy's if you haven't read this, please do so, it's interesting:
http://forum.audiogon.com/cgi-bin/fr.pl?fcabl&1111377651&openfrom&1&4#1