The Goldring NS1000s are absolutely stunning for £50. They're currently devalued on ebay because so many people have bought them to sell from play and flooded the market. They hiss slightly in active mode, which otherwise sounds great - detail on par with HD600 (Edit: I'd better qualify that - I've not head HD600s through a really good amp) and some of the most natural sounding vocals and string instruments I've heard in a headphone. They sound pretty dreadful without an amp in passive mode (bloated uncontrolled bass, and recessed everything else) though. If you're in a noisy environment the hiss is much quieter than any noise being cancelled.
Add an amp in passive mode and it's a different story. With a Fiio e5, they give my Creative Aurvana Live! set a good beating (the CALs are essentially the same OEM model as Denon AH-D1001). I can hear that there's potential for improvement with a better amp as the detail and some of the soundstage from active mode (which uses a built in amp) isn't quite there.
Basically - you're getting a closed version of the Goldring DR150 (same drivers).
Edit: I also have the s-Jays, which are very good. Noise reduction wise, they're about as effective as each other (if you use the s-Jays foam tips - the rubber ones let in quite a bit of noise) but the s-Jays don't hiss of their own. The s-Jays are quite sensitive so you'd better use a clean source. I'm very pleased with both the s-Jays and the NS1000s. Unless you're playing either of them at dangerous volume nobody is going to be hearing your music. NS1000 sounds better but I find the s-Jays more comfortable and there's the obvious portability issue.
Further Edit: I have also demoed the PX100s and HD201s briefly within the last few weeks. Source was only a walkman mp3 player but IMO the NS1000s totally outclass either of them.
Yet another edit: someone doing a review giving an A/B of the NS1000 against Bose Noise Cancelling Headphone (not sure which ones) and Grado SR80s
http://www.audaud.com/article.php?ArticleID=4232 - please note they weren't using a dedicated headphone amp for passive mode and these things are pretty current hungry - hence the comments about them not sounding good when turned off.