I guess I'm not familiar with the concept of 'let them have it' and want to keep the things I work for. So, you said no thing is worth taking a life but said you would confront a thief, which is likely to lead to a confrontation that would put your life in danger. So, according to that theory, you should just hide under the bed and let them take what they want and don't confront them at all.
I will explain it to you one more time...please read slow.
I would not shoot someone specifically for trying to steal my things. I would attempt to stop a thief, and if in the process the thief made me fear for my life, then yes, I believe deadly force would be justified.
I hope you aren't saying that you would shoot someone that was trying to steal your vehicle. You would be charged with, and likely convicted of murder.