My passport.
This is based on when I was talking to someone I met who's house burnt down and who lost everything in it. He had to restart by trying to prove his identity to his bank etc. Said it was a right going on.
PC .. it cost a lot, there's a lot of work on it and I'd be bored without it. Hopefully the Mrs will be able to carry it on her back while I get myself safe ..
I can't think of anything to be honest.... guess I'm not really into "stuff" - photos are all on a cloud somewhere. Might grab a banana & watch it burn.