oris98,
Furman has a very extensive line of line conditioning products ranging from $100 to $3500 or so. They all protect your gear to a greater or lesser extent and 'clean' the sound.
The units below $1000 or so are line conditioners....filters that scrub out grunge. Many feel they these type of conditioners scrub out music, too. It is a matter of debate.
The higher end units (I think, starting at about $1400.00) are balanced power units. They essentially split 120 v line to 2 60 v balanced feeds...reducing noise up to 16db or so.
Balanced is a big, heavy and expensive way to go, but less debatable as to it's positive effects. Most of the debates around it are debates of what brand is better, what brand is better value, etc...yet it remains mostly superior to traditional line conditioning (tho more expensive).
I have heard pretty stupendous things about Furman's IT Reference, but at $3500.00 it outta' shine my shoes when asked!
I've owned the PS Audio Power Plant P300 (quite good, I've thought on low powered equipment) and am now getting a BPT Unit. You may also want to check out Equi=Tech, Blue Circle, ExactPower for more options n balanced power technology.