What hardware, apart from your PC, do you find essential to your business? If you don't have one already, I recommend getting an uninteruptible power supply (I'm sure you have them for servers, but get one for your dev machine too). We're having a thunderstorm here right now that just knocked out the electricity for a few moments. The lights went out but the PC just kept on going. My UPS has saved me three times in the past five years, and I get a glowy smug feeling each time it happens. Laptops are also good in this regard. I once had to use the light from my laptop as a torch. For the rest of my equipment I use plain surge protection which has also saved me a few times.