I just think it is funny that Lucasfilm's last release of the movies in '08 was a boxset of the PT and a boxset of the OT.
George Lucas Commentary on ROTS DVD, "It is one big movie, and it is suppose to be watched 1-6, and shouldn't be looked at as two trilogies."
I guess it is still two trilogies when it comes to marketing and making money on SW;)