There are a number of different problems that you can potentially have with your power. The worst is lightning hitting your house, which is, of course, extremely rare and unlikely. And a simple surge protector won't do anything to guard against a full on lightning strike anyway. You need protection at the electrical panel itself for that, so it's a moot point in this discussion.
There can be a surge from the power company's end. And that's what a typical surge protector guards against. These are also rare, but it's a bit like any form of insurance. You never need it until you do! And then you're glad you have it
You can get dips and peaks in the voltage. Not full on surges or brown outs, but just variances above or below the nominal 115 Volt supply. A voltage regulator can keep the voltage steady. This isn't really necessary since almost all electronics are designed to use a range of voltages.
There can be electromagnetic or radio frequency interference or "crosstalk" within your electrical system and wiring. RFI & EMI filters can eliminate any of this interference, while having independent filter banks can eliminate crosstalk between devices that are all plugged into the same filtering device. Most homes have some level of interference in their electrical system, but the severity can vary widely. Items with large motors, like refrigerators, washers & dryers, air conditioning units, and vacuums and hair driers can often dump a bunch of noise and interference into your homes wiring. You might have noticed static or noise in your audio video system when such devices kick in. Or they might cause your lights to dim, which goes back to voltage sags and voltage regulation. So this form of "power conditioning" can be helpful in most homes.
Finally, there are brown outs and black outs. These days, we have a lot of devices that need continuous power. Projectors need cooling fans to protect the lamp. DVRs will lose recordings in progress and menu settings. Videogames in progress need to be saved and shut down properly. Anything with a hard drive could lose data. Anything with a cooling fan could potentially run into an issue with excessive heat build up.
The solution is to have a battery backup uninterruptible power supply. To me, having surge protection and battery backup are the two most critical parts of power protection. And I think everyone should have a good battery backup UPS protecting their DVR, display and any other devices that would benefit from never losing power. Filters are also nice to have, especially if you've ever noticed static or noise in your system.
For all of this, there is no better company than APC.
apcav.com lists APC's AV-oriented products. The most cost effective are the J-Type products. The J25B is a particularly great value and widely available. The J35B adds voltage regulation for a higher price tag. The J15BLK is great for when you need more battery protected outlets, but the price is significantly higher.
The J25B really is the best deal and gives you all the most useful protection that most typical home theaters will need at an attractive price. It IS a couple hundred dollars though, and some folks will baulk at that. But when it saves an important DVR recording in progress for you, you quickly realize its value!
Monoprice does sell a battery backup UPS unit for a lower price, but I've never used it myself, so I can't vouch for it. APC is the gold standard for power protection though. I trust them. And I think the J-Type units are worth every penny!
