[Quiet Man Cometh]

You know, febreze is not a bad idea actually. Things like that or pepperspray are probably better to have around than some weapons. I don't think it's a good idea to stash a weapon nearby unless you really know how to use it. You'd be in trouble if you had a knife on hand and the robber is better with it than you are. Announcing you have a weapon is also generally considered a bad idea if there's an intruder in your house because if that intruder has a weapon he is more likely to use it if he thinks you have one too. Self preservation and all.

Bar or chunks of wood in window tracks make dandy window blockers. There are also attachable door chimes that you can buy. Magnetic things that make a noise when they separate, ie when a door is opened. It would let you know someone is opening the window.