A good headset is the smartest investment you can make, especially if you are flying internationally.
I use a Bose X in a 744, and am noticing more and more of them being carried by other pilots. However if I were shopping today I would look for something that was lighter/smaller.
Would you rather see maintenance working on the airplane with good tools or with an adjustable wrench? It is the same with us -- quality work requires quality tools.