HE-400 - advantages of planar magnetic design (that speaks for itself), good build quality, accurate timbre, etc.
HD 598 - not amp dependent+ sensitive, energetic treble that doesn't fatigue, best soundstage I've heard (good for gaming/ movie), superb midrange.
DT1350 - build quality, comfort, sound quality... all spectacular for a closed portable design. V-Moda M80 gets special mention but it doesn't isolate noise well enough.
I was never too impressed with the Grado, Denon, or AKG lines. The D7000 sounded spectacular, a bit colored and unbalanced tonally, but very lush sounding; the D2000 had a far noticeable recessed midrange which just kills vocals for me.
I think it's hard to determine what the "best" headphones are because people listen to different genres. Obviously the AKGs would be pretty decent for acoustics music and the Denons for dubstep, trance, electronica,etc. I listen to almost everything but even then, I have different "priorities" when I listen to the music.