Can anyone recommend a good but not too expensive (under $100 if possible) UPS/battery backup? For some reason the power at my house has become a lot less reliable lately, and this morning was the 3rd morning this week I woke up to find the power went out and knocked out my iMac. I'm worried that one of these days, a surge will either kill my computer, or I'll be working on something that hasn't been saved and then I'll be up a creek. Thanks.