The Senn 280 Pros don't sound bad for the money, but the clamping force is intense.
Also, the all plastic headband had issues with cracking - not sure if those issues
have been addressed by Sennheiser.
The 380's, which I brought home on two separate occasions for listening, are just
incredibly lifeless headphones without anything to distinguish them except their comfort.
No sparkle, no deep bass, and a flat, diffused sound.
I had the AKG 271 II for about a year. Finally sold them due to their weak bass.
Beautifully made with a very clear and precise midrange.
The Shure 840 are nice sounding headphones, and I have no problem recommending
them in their price range. Be aware, though, that they are heavy and clunky.
And though it seems that people here have started to shy away from recommending the Audio-Technica
ATH-M50, it's still IMO an excellent value - maybe the all around best value - in its price range.
Another phone to consider is the Ultrasone 780 which is selling at about 150 these days, down considerably
from the 200 or so it had been selling for over the past few years. It has a distinctive sound signature with
a little extra top and bottom, but it's a really good listen nonetheless.
And still there are other good choices available, such as the Grado 225i.
(Note - when I speak about price range, I'm referring to street price.)