I was thinking along the lines of chocolate bars, Tea bags etc. that isnt easily obtainable in the USA and other parts of the world.
Its not easy to give a complete list as there is so much! on top of that, im not 100% sure whats sold in the USA with the same name and if its actually the same product.
Examples of Chocolate bars available are here: http://www.cadbury.co.uk/ourproducts/today/Pages/JS_bars.aspx?category=bars
Tea bags such as: PG Tips, Tetley, Twinings that are FAR better than anything you can get in America. (assuming you like English Tea)
Id also be happy to post products to the USA and other countries from websites and shops that don't currently ship to the USA.