Dana Thomas wrote in the NYT T: Style Magazine that when she looked into a true, non-reversing mirror she was actually frightened by how unfamiliar she looked to herself.

''Are my cheeks really this fat?'' I shrieked. In the mirror, I resembled Mr. Potato Head, all bulbous protrusions.

It's apparently an intense experience, seeing yourself the way the rest of the world sees you. True Mirror, a Brooklyn company, is hoping it's a sensation we all want to experience. A True Mirror is actually two mirrors housed together in a box that create a sort of 3-D effect.
I so want one, even though I know I'll obsess over everything I see. I won't let myself get one, but you can get one custom-built for $149.
Oh and check out True Mirror president John Walter's theory about side hair parts and US Presidents (this is a link to a pdf).