And if you don't need it to be free, there's Sizeup http://www.irradiatedsoftware.com/sizeup/ http://www.irradiatedsoftware.com/sizeup/ . Spectacle looks nearly

And if you don't need it to be free, there's Sizeup http://www.irradiatedsoftware.com/sizeup/ http://www.irradiatedsoftware.com/sizeup/ . Spectacle looks nearly as nice as Sizeup though.