Film1.nl got the poster below from the Cinema EXPO in Amsterdam. The poster, featuring Channing Tatum as Duke, reveals that the full title for the movie is G.I. Joe: Rise of Cobra.

Hasbro has bought the domain name GIJoeRiseofCobra.com, so it is a pretty good indication that it will be the title. I suppose just G.I. Joe would have been a bit boring…