I'd go with the HD598 for their extreme comfort for movie watching. They are also fairly easy to drive, although they can sound better with a better amp/dac (as with most good headphones). So E6 should have no problem getting a good bit of volume out of them.
Grado is not would I would choose for movie watching because of both their sound signature and comfort, and I like Grados. For movies, I want a headphone with decent low end bass extension, and that's not Grado.
To find out about a headphone model, google using "head-fi" as a keyword: https://www.google.com/#q=Denon+AH+D340+head-fi
Incidentally, for a closed headphone, the Soundmagic HP150 have a very good soundstage. Comfort is pretty good (to me). I have them, and I would use them for movies before my AKG K612, which are open headphones with a bit larger soundstage because of the deeper bass. Better deep bass extension than you'll get from the Senns. They have just been released in the last week, so might not be available to you. They are a revision of the HP100, which have a better cable setup, different looking cups, and better case. In terms of sound, best guess it that they might (or might not) have a touch more bass and treble than the HP100, so you could go by reviews of the HP100. Ask SteveHiFi in your other thread. He has heard the HP150s and could tell you how well he thinks that they would work.