To guard against power sags, you need an uninterruptible power supply. Depending on the UPS and your equipment, the battery may run your PC for as much as 20 minutes, which is plenty of time for a graceful shutdown. Replace the suppressor every few years. It's not a generator. Use it to do something it wasn't made for, such as running a printer, vacuum cleaner, or other power-cycling appliance.
Every wire counts.
Protect everything that connects to the PC, including phone lines, DSL and cable modems, and network wiring. If yours doesn't, grab an extra phone-line protector. When the power comes back on, your equipment won't be harmed. Leave one lamp plugged in and turned on so you'll know when the power returns. Dedicate your power.