According to wikipedia, there are 24 states that have laws where you can use deadly force against someone for criminal trespassing. If you look at this chart of violent crimes per-capita in different states in the US, you'll see that there is no correlation one way or another between crimes and having a "castle doctrine."
http://www2.fbi.gov/ucr/cius2009/data/table_05.html
Unfortunately the list is in alphabetical order. But, you can clearly see that being able to shoot someone for simply being on your property or stealing your property has very little correlation with violent crimes. I suspect this is because being able to kill someone for being in your house does not prevent crimes in general from occurring, but rather has the possibility to protect your life when the crime is already occurring.