Everything I have (outside of MP3's, video files, etc..) stays within the confines of REMOVABLE MEDIA which is inserted when I need something, saved back to that removable media, and then that removable media is removed from my computer.
I also maintain multiple COPIES of my removable media so I don't have a single source of failure for my information.
If anyone (NSA, etc..) is going to hack into my computer they're not going to find jack squat.
Yes, I know my actions are rather extreme however extreme times call for extreme measures.
I think your procedures are sensible and are maintained for good reason.
But if someone is looking to bring harm, a way around your measures can be found.