How do I secure my house against intruders?
Some tips I remember from an interview with a burglar a few years ago (can't find a link now):


Make it difficult for someone to conceal themselves while breaking in.  If a burglar has to be in full view of the neighbors while he breaks in, it increases the risk of him getting caught.  Avoid tall/thick shrubs around your windows and doors.  Avoid privacy fences.
Having good exterior lighting on a timer helps, but the best thing is a motion sensor floodlight.  When a motion light kicks on, it says "hey, something's going on over here", which will draw attention to your house.
Those little solar walkway lamps aren't bright enough to matter.
Avoid having stuff in plain sight that says "we have lots of $$$".  If you have an expensive car, keep it in a garage.  If you have nice stuff in your house, keep your blinds closed.
Burglars case a neighborhood before they rob it.  They know when you leave for work.  They know when your neighbors leave for work.  If you have neighbors that are home during the day, it will make your house a riskier break-in.
If you have a security system, don't put one of those "Protected by ADT" stickers on your door.  Knowing which brand of security system can provide enough info on how to disable it.  Get a generic sticker.
Get a dog.  The bark is more important than the bite.  A little yappy dog can be more of a deterrent than a German Shepard.


Remember, the goal isn't to make your house completely break-in proof.  It is simply to make your house a less attractive target than the other houses in your neighborhood.  Look at the surrounding houses and adjust accordingly.  You don't want to be the lowest-hanging fruit!