Hi, for the past year or so i have been looking into the same things as you and hope i can be of assistance. i have been meaning to put up reviews and this has prompted me to at least provide some infomation.
It is true, the Goldring NS1000 do leak sound when pushed really hard but i currently use them in an office environment and have never had any complaints. office is open plan and have people quite close to me on the left and right. they are comfortable over long perdiods and sound excellent. My setup is such that they are plugged directly into a Firestone Audio Fireye DAC headphone amp, which is in turn plugged and powered via USB into the laptop. This results in an open and excellent sound at low (yet fully acceptable) volumes. this means that no sound is majorly leaked and the quality is of a decent standard.
Recently however after owning the Goldrings for over a year i sort of got bored and wanted to try some others, i also thought that i can keep them for commuting and by some heaphones which have no noise cancelling so the money spent is not purely for the NC technology, My travels took me to AKGs Closed Back 271 MKii headphones.
Bought them for £120 and i have since sent them back for a refund. Basically the detail was much better that the Goldrings and i am sure that after being fully 'run in' they would have surpassed the sound quality. the auto mute funtion when you take them off your head was a nice little touch as well. i sen them back tho because they were not comfortable over long periods (in my opinion) and there was a lack of excitement. They are designed for studio monitoring and the bass is exceedingly tight and refined, a bit too much for my liking. the other thing is they are massive. the AKG range may not be up your street as well if you are only only using na i phone or ipod to drive them. they require more power than most.
I will soon be ordering a pair of Audio Technica's A500 closed back heaphones to see what they are like. will let you know if you care to find out.
In short, i love the firestone fireye tho. previously had a sound blaster sound card running the headphones and this just blasts it out of the water.
Hope this helps anyway.