Well, I've watched Lily several times sitting in front of my mirrored cabinet, playing with a toy and watching her movements in the mirror. It was very obvious that she was thinking about what she saw. Of course I don't know if she knew it was her she was watching or if she just thought the cat in the mirror copied her actions..
And remember when she saw a photo of herself posted at Pet Talk. First she was afraid of it and approached it carefully, then she sniffed it and was looking for the cat inside the monitor! But I'm sure she wasn't aware that it's her!