Last night's power outage sparked this reminder: at the first indication of power fluctuations, turn off and unplug any electronics you don't want to lose.
Consider using a battery-backup unit for the main components of your computer system - tower, external drive, router, cable modem, printers, monitor, speakers. In that order. Besides adding good surge suppression to the system, the battery also smooths out brownouts - which are a bigger danger to electronics because they happen all day long. Every day.
Me? I lost a nice set of speakers and sub-woofer. C'est la vie.