If you choose to go after an intruder with a weapon, you have to be able to prove afterwards that the weapon was not stashed under your bed for the purposes of bashing an intruder, as that becomes pre-meditated, as in you've thought of it, and then stashed the weapon to facilitate it.
If you have a ninja sword under your bed, to defend your home, and you stab someone, you go to jail. If you have ceremonial swords displayed on the wall of your bedroom permanently, as an ornament, then you have a reason for them to be there and can show that you only reached for it out of need. You can have a hammer lying around due to DIY jobs, so thats good too. but if you have a 2x4 with a mail sticking out of it, or a baseball bat, yet don't play baseball at all, then a scumbag lawyer would make that stick, as you have the bat there for the purpose of beating an intruder, which means you planned it, which makes it pre-meditated.
A heavy lamp is waht the police suggest round here. No-one can touch you if you bash someone in with a heavy lamp...