Regardless of the handbag or rucksack, it always contains a Swiss Army knife. Why? Because I am a child of the 80's and I read the SAS Survival Handbook and fully expected to be nuked, shipwrecked or competing with a gecko for the last drop of moisture in a desert somewhere. But mostly nuked.
Consequently, in 1986 I had a homemade survival 'kit', consisting of a leather rolled up pouch, into which I carefully placed waterproof matches (snapped in half so the woody bit could be used for kindling - always thinking people!), fishing line, vitamins - so important to keep those B6 levels up in life or death situation - and a few other essentials. I also had a very non health and safety camping knife with which to garotte bears etc.
The certainty that the world would resemble a post-apocalyptic Mad Max scenario lives on in me in the form of a talismanic penknife habit. And mighty useful it is too for breaking into recalcitrant packaging from the likes of Pret A Manger.
I'm not sure it would be much help in a nuking situation though although it is quite handy on walks.