Most of the "smaller" stuff, I don't sweat. The only real things of value I have (at this point) I keep on my person (iPhone, leatherman, maglite). Everything that would be "sitting around" is going to be stuff like band-aids, sharpies, etc., all easily replaceable consumables. The exception to this is Joseph (yes, I've named my laptop.) Losing him would be terrible, but that's where homeowners/renter's insurance comes in. In my area at least, $10/mo gets you a $250 deductible with up to $20,000 in event of fire, flood, theft, accidental damage, etc. I keep a good backup of all my files (daily to an external harddrive and offsite servers (google docs is similar to what I use) so I lose 24 hours of work at most, and then simply replace the laptop. A pain, yes - but worst case scenario I'm out $250 instead of $2500. Most of the other "expensive" tools are owned by the theatre and provided, so I don't need to worry about those.
Just my $.02.