Help choosing Power Conditioner


Completely new to this area. I would like a unit that:
a) regulates power, keeping it within the 120v range.
b) provides good and long-lasting surge protection
c) can be used with a power amp as well as preamp, and sources all together
d) Hopefully helps the audio, making it more open and dynamic without negative effects.

I need to say under about $750 used. My candidates are:
Monster HTPS7000
Monster AVS2000 (how are these two different)?
PS Audio Power Director 3.5
Blue Circle MR1200 Music Ring
Any others...
Thanks!
kck
TVAD,

No dig on your post at all, I was commenting on the exchange between Snofun3 and Dedicatedaudio. I guess I was too general. I like when folks point out listings in posts, just nice to know if they have more then a passing interest in the transaction. Sorry for any confusion.
Maineiac, thanks for the explanation. No worries.

Jman66, you make a good point about the humming. I own a OneAC unit that does have transformer hum, and I have moved it to my HT system where it's located in an area that masks the hum. Readers should note that we are referring to hum coming from the conditioner itself and not a ground loop hum in the loudspeakers. At least that's not the hum I'm talking about. I suppose I shouldn't speak for Jman66.

It would seem one could use a product like a PS Audio Ultimate Outlet Humbuster ($299 new, or less used) in conjunction with a Powervar ABC1200-11, and have top quality, hum-free conditioning for $528 or less. That beats most of the audiophile transformer based conditioners.

Also, I have low level hum in my VAC power supply and in my First Sound power supply, so this is not limited to power conditioners with torroidal transformers.

I must have gotten my Powervar from the same guy as you Tvad. These things are the real deal and at 229 so much cheaper than other iso-transformers out there. I have no hum issues at all.
Mike
Tvad - Yes, I was referring to the transformer hum. The Powervar I used (ABC1200) had varying levels of hum by day, sometimes quiet in the morning and then noisy as heck at night. I tried some additional damping of the toroid, helped a little bit but not enough.