First make sure the bump is something you have to defend against. I have a son that used to sleepwalk. And then don't get me started on wooden frame houses!
But if push comes to shove...
First off, +1 on this
To be armed with only a knife for HD is stupid
Second, most kitchens have much larger knives than any hunting knife.
Third, +1 on the baseball bat. As long as you're not facing an armed burglar you're better of with the longer reach of the bat. Knives are intimidating but only if you know how to use them. And still you have to get way too close for comfort!
And fourth, with the price of a new Rem. 870 Express under $300 and a currently running $30 mail-in rebate, there's really no reason not to be prepared. A shotgun makes for a great security blanket. :-)