Increasing the limitation on the unified credit used to determine the Maryland estate tax from the amount corresponding to a $1,000,000 exclusion amount under the federal estate tax to the amount corresponding to a $2,000,000 exclusion amount under the federal estate tax; repealing a requirement that the tax be determined without regard to the deduction for State death taxes under the federal estate tax; stating the General Assembly's intent; applying the Act to decedents dying after December 31, 2007; etc.