I'd add to that list the AKG K550s. Closed-back, too!
I picked up a pair recently new-in-box-secondhand just because, and they are really very, very good. I've still got the Senn HD565 Ovations I've used for the last 15years, which I bought over the raved-about HD600s of the day because of the livelier/more natural/less dull presentation*. Also had Beyer 5xx in that time frame. And some Stax - I still have and use the wonderfully eccentric Stax in-ear phones (superb, actually, esp with modded-to-the-point-of-homebrew amplifier, if you don't mind sticking 650v bias in each ear). The AKGs have put the rest back in the cupboard.
Comparisons in my view: the AKGs don't have the prominent 'warmth' bump of the Senns I've heard & am used to, no the bass is much more extended, flatter and realistic overall. The AKGs also have a more realistic/even-handed mid-treble balance; and the detail/microdynamic rendition is superb - exciting, but natural, not forced; long listening sessions are a pleasure. The things are 32ohm but seem easily driven - sound great just plugged into my macbook pro and sensitive enough that '50% full scale' of teh macs vol setting (rel 1v rms output) is more than loud enough for me.
I'm slightly stunned how 'open' they sound for a closed-back phone - you really, really wouldn't know it, when many closed cans are (IME) really obviously coloured. This means no problems with background noise and low listening levels, nor annoying the SO!
If this reads like a rave, so be it. They are really good and worth the £180rrp.
* the 'negative traits' i heard in the HD600 remains in the more expensive Senns I've heard since - a slight tendency to a bit limp/bloomy sound, Senn's 'free-field equalised' model sounds a bit warm and flat for my taste, demands a very good headphone amp to live with, and tends to slightly rob the presence range of energy - which is a personal matter of taste of course.