I've bought my own Sennheiser HMEC45-KA for use on B757/767s and am very happy with it. £252 + £19 for delivery from Germany, incl tax.
The HMEC45 has open ear pieces and only kills 10db of noise (half of it) rather than the 15db than the ear-muff type noise canx headsets provide. This suits me fine because I can still hear the cockpit door open and the other guy doesn't need to use the intercom. I switch it off for tkof and ldg (and generally below 10000')
Find myself wondering why I didn't get one years ago.