There should be no possibility for an intruder to be scared off by the sound of you racking your weapon since it should already be chambered long before an intruder is ever close enough to hear it.

With the use of quality doors, windows, locks, motion alarms and lights, you can pretty much make your home nearly impossible to enter without you being alerted. I think it ethical and legally prudent to avoid shooting someone if there is anyway around it. You must positively identify the possible threat, so using lighting to some degree is necessary if it's dark and give verbal warnings when appropriate, which is almost always since 911 can hear and is recording the incident. The specific tactics that would be most effective largely depend on the specific scenario, layout of your home as well as time of day the break-in occurs. There is no one size fits all plan.