Monster had a great deal on their $399 HTS3500MKII several years ago for $150. I bought one and hoped I'd bought two.
* 10 outlets, 3 coax, 1 phone
* Monster Clean Power™ Stage 3 filters optimized for digital, high current audio, and video applications.
* $100,000 Connected Equipment Warranty.
* Protects coax lines used with cable TV, DBS, and DSS equipment from surge pulses.
* Ultra-high 2775 joule rating provides full capacity surge protection.
* 12 volt trigger input for remote turn-on of switched outlets.
* Dual Mode Protection provides audible and visual alarm for maximum protection and performance.
* High sensitivity volt meter measures incoming voltage and shows AC power fluctuations.
* Component-width chassis suitable for rack-mounting or stacking (rack "ears" included).
I noticed more of a difference with video than audio, but still an improvement for both. I also have the HTS2000 I purchased for $49 about the same time. Both provide an improvement, but the 3500 is definitely better. The only caveat are the lights. A dimmer is provided, but still noticeable. They can be a distraction, so I block the lights while listening or viewing.