I guess CGI motion-capture nudity doesn't count as much as live action, fleshy nudity: Beowulf has been given a PG-13 rating by the MPAA. On the other hand (and thankfully) the Johnny Depp starring film version of Sweeney Todd will be rated R. I'd say that's appropriate for a movie about a throat-slitting barber that grinds his victims into meat pies.
Here are the detailed descriptions from the MPAA for the ratings:
Beowulf: Rated PG-13 for intense sequences of violence including disturbing images, some sexual material and nudity.
Sweeney Todd: Rated R for graphic bloody violence.
So there you have it. Now let's wait and see if the upcoming movie Hitman actually ends up with the R-rating that Fox says it's shooting for or whether they'll strip it down to a PG-13.
Thanks to Firstshowing for the heads up!