Here in the u/k we can't keep guns around the house unless locked in the correct style of locker, unloaded etc.

So what makes a useful weapon to keep upstairs incase of a night visitor?

A kitchen knife? no thats premeditaed!

My choice is a CO2 fire extinguisher, a blast of freezing co2 into the face is quite disturbing & disorientating, also the empty cylinder is heavy when used offensively & will ward off a baseball bat or similar. a very good close combat weapon to defend the top of the stairs.
Best of all it is sensible to keep one upsatirs in the event of having to get the children out if there is a fire at night m'lud!
You can follow up with a powder ex. This will clog the eyes & as the victim runs away will leave a trail & contaminate the car/his house etc. useful for the forensic boys & witnesses.

If they come to steal your video player, dvd machine etc. then the best bet is to offer to carry the items to their car, after all you get new for old & nobody gets hurt!

Skipy