Establishing separate classes for property tax purposes for land and improvements to land; establishing a new subclass of land for land that is used a principal place of residence; exempting improvements to land from the State property tax, with specified exceptions; exempting from the State property tax the first $15,000 of value of agricultural land and the first $40,000 of value of land used as a principal place of residence; applying the Act to tax years beginning after June 30, 2006; etc.