These days, more new homes are being built with sprinkler systems. Here's how they work. Sprinkler pipes are hooked up to your home's existing water service and remain under constant water pressure, thereby cutting down reaction time. You can get sprinkler heads that are small and unobtrusive and individually heat-activated so that only sprinklers near the fire are triggered.
For more on fire safety, consider:
Radio: Fire Drill
Residential Sprinkler Systems
9 Ways to Boost Your Fire Preparedness