The mice are definitely winning.

So, this afternoon before I went out, I went around the house baiting all the mousetraps with the peanut butter I bought just for them.  On both the trip plates and the springs, in the case of the old-fashioned spring traps.  Just now, I looked around to check the traps.

The mice definitely love peanut butter.  They cleaned all the peanut butter off all the traps in the kitchen.  Without tripping a single one.  They don't seem to have found the ones in the office next to the printer.  I'll have to hope they like the poison I also bought, since they seem to be too clever for the traps.