The best app for this on the iPhone that I have found is "Groceries" from
http://www.sophiestication.com/groceries/.
Despite the name, you can make any check off list you want. I use it for e.g. Winter Camping List (did you remember your down gloves?). It's also useful, because if you go to pack your 3 oz of mouthwash, only to find that you are out, you can easily add it to your "Grocery Store" shopping list. It's better than OmniFocus for this checkoff list activity.