I'm off to get a new 2010 27" i7 iMac and I'm wondering what kind of UPS to get. From what I've read the type of PSU the iMacs use is supposed to have a power source that can provide a true sine wave, but I don't know if this is actual necessary for the iMacs in particular. I've been looking at this APC unit which provides a stepped approximation. I don't know if this will suit the current iMacs, but a UPS with a true sine wave gets to be extremely expensive. If the iMac really does require a top of the line UPS are there any good surge protectors that can be had for $100 or less? Battery backup would be nice, but reliable surge protection is really all I need. Thank you.