Things voldemort should have made into horcruxes:
1. A penny. He then should have gave that penny to a complete stranger and told him to pass it on. The result would be Harry Potter never being able to find the penny.
2. His underwear. Who would want to take someone's underwear off of him?!?
3. A dead battery. Who would suspect that?
4. Lily and James' tombstones. Could harry destroy his parents' graves?