power conditioner

I can only speak for myself, based upon my two audio systems I have to say yes, I definalely hear improvement by using dedicated AC lines, and further improvement with a good high quality AC outlet. In addition to that, I also hear an improvement when using some type of power conditioning. Many times my amp sounds better when plugged directly into the wall.
Audio equipment reacts differently to various power conditioning, so it's a matter of trial and error and/or reading various reviews and hoping what you read about works in your situation.
Just yesterday I received my Power Core Technologies 1800, in my system, it's a killer out of the box and very reasonably priced. 
I agree with Lowrider57; "The goal is to lower the noise floor, provide stable power, and not restrict the sonics of your system".

"..they all have warts I cannot live with."

Hi stringreen,

The Ayre L-5xe is not one of the AC Enhancers I was referring to.

Best to you stringreen,
Dave

How important is power conditioner for musical system

The system can work without power conditioner so one is not critical to the system. 

"How important is power conditioner for musical system"

Key word here is "musical".

Best to you czarivey,
Dave

Power conditioners can harm sound and help the sound. Some have spike and surge protection some do not. Some work well with amps some do not. Yes it can depend where you live and what type of power you have coming in to your house. Dedicated lines our nice, but they to can some times benefit from some type of conditioning or surge and spike protection. Some recreate a perfect sign wave some filter. Both can help or harm or restrict your system sound. Best to try as many as you can in your system Most company have a 30 day money back guarantee. Some will sound good with your preamp and disc player but not with your amp. Some will sound good with your amp but not the rest of your system.
For me i have used PSaudio P10 for years and never had a problem with it.(large amp straight to wall) used it in a home theater system and a 2 channel system. The sound i felt was good with it. Since i have done away with the home theater system and only do 2 channel now. I moved to High Fidelity MCo6 Hemisphere, really like what it does in my system it was a big improvement in the sound a cross the board(long break in). But on the down side i gave up surge and spike protection. 
Everyone has a flavor they like, you need to find one that works for you. What works great in your system may bring a another one down. Both companies are way easy to   talk to with no pressure and 30 day money back policy.
Good luck