I worked w/the Senn 280pro cans for a long time on their supposed high isolation numbers. Then I went to AT M50's for a couple three years and liked them well enough to give the 280's away. I felt the M50's, which lots of TS'ers have recommended were a little crisper on the whole. Isolation about the same but it was no longer a factor.
Then I picked up the
Senn HD650/HD6XX from MassDrop, (now just Drop). Wow. Nice jump for not much more $$$ Which is something you don't state as a controlling factor.
(The following weigh in between $140 and $220.)
While the bass of the Senns is not too forward, I think they are pretty well balanced. Open back & over ears is OK by me. I don't know how to rate them for a "big head" but as an adult male they're comfy for me.
I ended up wondering about their "re-rolled"
HD 58X Jubilee offering, as its signature was reputed to be a bit more bass colored, and they are... but not drastically so. I haven't done a lot of A-B listening with my Senns but if pressed, I'd say the 6xx is more balanced and "musical" while the 58X is a bit more on the fun and slightly brighter side. They require less power as well at 150 ohms, but the 6xx. at 300 ohms, blossoms with an amp. Both share the same form factor and parts and alt ear pads are available.
Drop also sells the
Beyer DT770 PRO and the
DT880 Premium cans which I've yet to listen to but, as you know, have large followings. These are not "X" versions that I can see unless they fiddle with cable options or such. I think the prices might be somewhat lower since they may be acting as an aggregator for Beyer and can make somewhat regular large orders.
Finally, I'm a bit of a can slut lately

, I really like the MassDrop treatment in the
Meze 99 Noir. Lovely lite pressure on the head fit, a couple of ear pad options and they sound like butter with a nice low end presence. They went for a vanilla version of the Meze 99 Classic cans which sport lots of gold accents and such. These look swell to me. I don't use them for mastering since they are obviously colored but they have a well behaved curve and I don't find them fatiguing. I've got them plugged into my home theatre and my two channel vinyl rig.
Lots of comments and user reviews on Drop for all these cans.
If you follow
this link you'll find the Drop Audiophile offerings. Many are ready to ship, more or less, others may be subject to meeting a "drop requirement" of a specific number of orders. They tout other lines such as Fostex, AKG, AT and HiFiMan as well as many IEM brands and phone amps.
Good Luck!