I own a slightly elderly Telex 750 which seemed a good idea at the time and mostly resides in a cupboard.
It's very comfortable and the sound quality is excellent, but the noise attenuation is nil. If that sounds right go for it.
If you want any attenuation at-all however, I'd splash out on a Bose. The difference a good headset like that makes to your ability to concentrate is always impressive.
G