Bose X is about $995 here in the US as I recall. Apparently it is the best out there (whatever that means).
I personally own the Pilot PA 17-79s. Now I only fly GA aircraft, so I have no idea what they'd be like in the cockpit of a jet. However, they are very light and comfortable. The perspiration factor was a problem for me with the seals. The solution was to buy cloth covers for them, and they are now a lot more comfortable for me. They are powered by an internal Ni-Cad battery. A panel powered version is available too as I recall. There's a debate about the internal Ni-Cad vs. external replaceable batteries. So far, I've had no problems, but if you forget to recharge the headset obviously you can't pop in a new pair of batteries.
Build quality is good and they look nice. You can adjust pretty much anything you'd like in terms of mic, headband, etc.
I was also considering the LightSpeed 25XL - similar price. The LightSpeeds are HUGE by comparison, but may provide marginally better sound absorption. All of this will be subjective and will depend on the aircraft that you regularly fly in. My GA trainer is bound to be noisier than a 757 cockpit
The best thing you could do, would be to go to an exhibition like the recent AOPA one here in California. There you can compare a number of the headsets.
Any other questions, drop me an email:
[email protected]