Thinking of buying a CyberPower CP1000PFCLCD UPS (1000VA/ 600W) Here's the breakdown: 1000VA / 600W (CP1000PFCLCD) 27" iMac: 310W Future LED Cinema: 250W External Hard Drive: 13.5W ( I think) Router + Cable Modem = 20W (Aprox?) Additional Hard Drive: 13W Total: 606.5 W Assuming the Devices are NOT at 100% load: <600W Are my External Hard Drive, Router + Cable Modem and additional hard drive estimates accurate? Is the UPS' sizing just right? Let me know what you think. Thanks!