Surge protectors--how many $ make sense?

Defense in depth: Absolutely begin with a whole house surgeprotector. It is the cheapest insurance known for everything electric in your home, especially if you lie in thunderstorm prone areas. If you have sub-panels, but one in their as well. Next is your point-of-use devices. Whether you decide to go with a simple quality suege protector, more elaborate power conditioner, or all the way to a battery power generator is up to you and your circumstances.

I would also check out Ting - www.tingfire.com - an electrical arc fault detector. State Farm just sent me one for free. Apparently they can detect 80% of all electrical fires before ignition. I get a monthly email report showing voltage fluctuations, outages, brown outs, and voltage spikes, which is kinda fascinating in a nerdy quasi-paranoid way. But the reassuring note that no faults were found does deliver some peace of mind. They're $99 with a year of monitoring, and include a pretty cool app, if your insurance company won't freebie one.

@rfagon Clamping voltage is a single dimensional specification, It means very little unless the clamping time is also specified. In the case of SquareD, their whole house surge protectors have a clamping time of 4-6 nanoseconds. When you consider that a single 60 Hz cycle is 175,000 times longer, you begin to understand how very effective they are in the real world. That said, the Environmental Potentials products are the real deal, and engineered (and priced) accordingly to their higher performance. The EP-HPS at $2400 isn't cheap, but their lack of pretense about their products is very appealing.