"Recent data from our honeynet sensor grid reveals that the average life expectancy to compromise for an unpatched Linux system has increased from 72 hours to 3 months. This means that a unpatched Linux system with commonly used configurations (such as server builds of RedHat 9.0 or Suse 6.2) have an online mean life expectancy of 3 months before being successfully compromised." [PDF Report]

Lifespan of a Windows PC: four minutes.