Link to Form 4457: http://forms.cbp.gov/pdf/CBP_Form_4457.pdf
List ANYTHING NOT MADE IN USA on form. If you look on line you will see where Customs has even confiscated clothing labeled as "Made In XXXXX" (other than USA). They usually will be eye balling stuff like electronics, cameras & equipment, firearms, shoes, fur coats, jewlery, etc. The more expensive it is...the more Customs will take a look at it. If you can live without it...don't put it of the form. Form is good forever once signed by a Customs Agent/Officer. You can carry as many 4457's as you need to list your items.
And also remember, until you hear, "Welcome to the United States" and walk out the exit door (when you get out of the yellow lined box on the floor) you ARE NOT A U.S. Citizen and you have NO RIGHTS. So don't whizz the officers off or you'll end up in the "Cube". Not a fun place but after two trips inside I know just how far I can push their buttons.
You have been warned ;-)