I recently tried out a Sennheiser ANR headset. It was "open-backed" so I could have both ears covered but still converse with other people in the flight deck. ATC reception was excellent, and it cut out all the low level noise, leaving a mid-to-high range hiss.
Unfortunately I found the headband extremely uncomfortable on my (bald) head, and I didn't feel the £400 cost was worth the discomfort!
Someone less follically challenged would probably be fine!!
