My one cat will attack everything, but she doesn't find it as interesting as the other one. The other one, however, *loves* her toy mice. She'll go wandering around, yelling with one in her mouth. She routinely drops the mice at the foot of our bed during the night, then in the morning, we step on them (and they have those little hard bodies) and they hurt! She also attacks the infamous invisible bug on the carpet!
My last cat, Smokey, she used to leave me presents every night. She started by dragging this Barbie doll out of a toybox and leaving it on my floor. Then one night, she drug pieces of Barbie clothes, up from the basement, to my bedroom. There was a pile in my room of Barbies and Barbie clothes, and a line of clothes going down to the box they were in. It was the most precious thing ever!