I never thought about the disease factor, or the chewed wires, or I would have done something about him sooner. :smack And of course Liam is right, they breed.
I do live in a northern state (Michigan) which is why the little rat is in the house in the first place, I suppose. Given that, I think the only reasonable thing to do is to kill him as quickly and humanely as possible. And why is it, as Yesh pointed out, that I have no trouble stomping on the spiders that migrate into the warmth of my living room every fall, but can't bring myself to kill a mouse?
I did check out the live traps, but I don't think I can justify spending $20 to save the life of a mouse. My hubby would freak!
Thanks for the input, everyone. Most appreciated.