Is there a standardized identifier for published media other than ISBN and ISSN?  

I'm specifically interested in movies, audio, etc.
I'd prefer to know about any international standards, if they exist.
My goal in asking this question is to be able to catalog on the web,
in a standard way, published works.

If not, has there ever been an effort to do this standardization?  If
so, who was involved, and what caused it to fail or stall?

If the media exist in digital form, you should check out the Digital
Object Identifier system:  http://www.doi.org/

Thanks.  It sounds like something that would be useful to businesses
w/ content to sell or buy, but not useful in a general context.

Not really, as the DOI concept is quite general.  I'm most familiar
with it's use in scientific publication, where the trend is to assign
a DOI number to every article that gets published (now that most
scientific journals are online).