This affects shipping prices more than anything else, so the "domestic" and "International" shipping prices can be calculated correctly for the country that the cart is located in. Currently those in non-US countries need to update the Shipping.pm file to adjust the $shipping_string in assorted places.
Could these strings (domestic, int'l etc) be added to the GlobalYams.pm file, perhaps?
On a related note, sometimes it's the country that determines if tax will need to be figured. In Australia starting 1 July 2000, I'll need to add 10% GST (Goods and Services Tax) to all orders placed by anyone in Australia. Luckily Yam's state tax feature will give me something to base the other tax on.