Belated Thank You to the Merchant Mariners of World War II Act of 2007 - Directs the Secretary of Veterans Affairs to pay a monthly benefit of $1,000 to certain honorably-discharged veterans of the U.S. Merchant Marine who served between December 7, 1941, and December 31, 1946 (or to their survivors). Includes service in the Army Transport Service and the Naval Transport Service. Exempts from taxation benefits paid under this Act.