I would reccommend the APC Back-UPS Pro 650 (serial) or 500 (USB). APC makes EXCELLENT products. My 650 has no problem running 2 systems, 1 15" monitor and 1 17" monitor with power to spare. I don't trust those cheap brands (cough...Belkin...Cyber Power...cough). When choosing, be sure to look at the voltage let through/clamping voltage. APCs are all rated at <40V some are as high as <400V. Also look at Watts not VoltAmps. Different companies have different ideas of how many voltamps are in a watt. Though technically they should both be the same.