I am not very familiar with metro applications as I do not have a touch screen computer or tablet. However their are some I use like skype, xbox music, Windows Phone app and the rest are games like ARMED!, Heros of Lakewood, Jetpack Joyride and Radiant Defense.
I am still very much on traditional desktop apps for the moment and will probably for the foreseeable future as I await a Windows based tablet for xmas.