I purchased the HTS 3500mkII from Buy.com for $159.99 and received a $50.00 rebate from Monster Cable. I then had a friend purchase another one for me so that I could get the second $50.00 rebate in his name. This may seem excessive, but total investment to this point was only $218.00. And if every last piece of equipment is not "Monster" protected, the connected equipment warranty is void. I am using one for my home entertainment center and to the other I will connect all of my computer equipment. The surge protection was only a secondary concern of mine, but it's nice that it's there, should anything happen.
My primary reason for doing this was that I had some sort of ground loop fault going on between my PC(Presario) and my receiver(AVR 240, Harman). Shortly after soundcard(X-Fi, Creative) install, I started up a music playlist. When the music finished playing, I noticed a vibration in the walls and thought my home's A/C had kicked on. Then I realized the drivers in my sub and floor standers(all speakers JBL) were radiating significantly, despite the receiver not being fed a signal.
There was a great deal of low frequency noise being fed into the receiver through the soundcard. Not the soundcard's fault. Primarily an artifact of the grounding issue and much electrical noise created by all the components in the PC.
When the first power center arrived, I tore down the entertainment center and connected everything through it. A huge improvement. The vibration in the walls was gone, the low frequency noise was no longer audible and the drivers were radiating so slightly as to be perceptible only by touch. I don't know whether the second power center will improve the issue any further, but I have already ordered a separate isolation transformer (Pureformer, JK Audio) from Markertek.com for $55.00+ship. Total investment $278.00. I agree that in most cases, this type of equipment is probably over and above what is need it terms of price, performance and features. In fact, previous to connecting the PC to the receiver, I had no such noise issues and the sound was fantastic. However, for my current applications, these items were exactly what I needed.
Personally, I don't watch much TV and my music is very important to me. So I don't think of it as excessive when considering some reviewers here are paying $3000.00-$4000.00+ for their televisions alone.