Don't forget the requirement to fill out the on-line visa waiver pre-approval for you both prior to travel: ESTA (Electronic System for Travel Authorization). This basically asks the same information as the green visa waiver form filled out on board and is not over onerous. It does require a destination address. This is a new compulsory requirement for UK nationals (and other visa waiver scheme nationals) since your last visit. While this did not greatly speed up immigration in Chicago I would imagine that not doing it could greatly complicate things for you, either at check-in or in the immigration hall. Congratulations - Us 'groundhogbrits' have been married 20 years this year - enjoy the honeymoon.