Slashfilm reports that Lucasfilm has filed for six different titles for the fourth "Indiana Jones" feature with the Motion Pictures Association of America. The six that are apparently being officially considered as titles for the fourth film are:

"Indiana Jones and the City of Gods"
"Indiana Jones and the Destroyer of Worlds"
"Indiana Jones and the Fourth Corner of the Earth"
"Indiana Jones and the Kingdom of the Crystal Skull"
"Indiana Jones and the Lost City of Gold"
"Indiana Jones and the Quest for the Covenant"

The first, "Indiana Jones and the City of Gods," has long been the rumoured working title for the production (and arguably the best of the batch, though like 'Destroyer' and 'Quest' as well myself). Should no other objections be raised, the studio will be clear to use any of these titles in two weeks.