How much should a person spend to get a decent power conditioner?

It’s sounds like you are after both surge protection and trying to improve the sound? On surge I use a whole house, not expensive, but you need to replace when the pilot lites indicates the MOVs are no longer effective. Plus I use a very large commercial isolation transformer with its own surge protection panel feeding a dedicated subpanel to dedicated lines. The wiring isn’t costly, but the iso-transformer can be unless you are sourcing the naked transformer and have a way to install it to meet applicable code. (My unit is about the size of a large air conditioning box and sits outside- it is weatherproof and was built to spec as a finished product).
My concern about black boxes that actually do anything is that they affect the sound. I haven’t used any of the (end) point of use for a while for the main hifi for that reason, though virtually every other expensive appliance and my second hi-fi system do use point of use surge protection.
Dedicated lines are nice, no guarantee of noise free from common grounding with house and no surge protection. I would look at subpanel type protection for the dedicated lines if you can do that.

I’ve never messed with high powered regenerators which can get costly -- I was always concerned when they were (only available as) smaller units that they constricted current to the amps.

@helomech- I believe the brick wall technology was developed by Zero Surge out of Frenchtown NJ, who sell their own units, from two outlet jobs to industrial sized panels. 

@newf27- Did the additional grounding help with your low level hum?
Because that sounds like a grounding issue. Those can be very troublesome to sort, in part because of the different grounding schemes within the components comprising a system that, when connected together, create a ground loop.

@folkfreak - I'm a completist in that i cannot read "nattering nabobs" without the complete phrase. :)
I was trying to discern what you are using- I remember some posts about Synergistic Research active blocks, and saw that at one time you had the Equi=Tech wall cabinet. You are now using a Torus isolation transformer or did I misread? I assume you found some benefit to 'conditioning' of some sort even with balanced power? I gather from my cursory read of your set ups that you don't have a traditional 'black box' power conditioner installed?
Call me agnostic on the subject. If it helps, great. I think try before you buy is the watchword for anything over a modest price.