Is some hiss/hum normal?

[afountas]

Does anyone have a rig that is nearly silent?  or do you always get some hiss/hum?

I have a good number of effects running in my chain. but everything is either running on an isolated power supply or a furman power supply with Isolated outlets.  All the power supply cords are neatly organized and have very limited intersection with instrument or effect cables. 

However, I do still get some noise from the rig, it's fairly minimal.. which is where my question comes from.  Will some noise always exist or is it possible to get it to a nearly inaudible level when nothing is engaged.

pic of the rig:

http://strangedesign.org/forums/index.php?topic=2577.0

[trunkyfunk]

I think it is inevitable for the PU to pick up EM waves, especially with the compressor on. This worsens if there are any dimmer switches on or any small engine things like fans.

https://www.youtube.com/watch?v=Nakpj_Mee0Q