tatalope, noise cancelling phones are a bit more costly than regular phones. aside from philips, sennheiser also has noise cancelling phones, px 250, though it might cost a bit. i think they have a newer model.
another option is bose quet comfort, though i have no idea how it sounds, and how much it costs. but somehow, i feel that it costs much more than the sennheiser. bear in mind also that you need batteries for the noise cancelling function to work.
you just want a pair of cans to block outside noise? have you considered a mid-sized sealed phones?
regarding arnold's tube head amp, check out this thread:
ArnoldC's Tube Headphone Amp
if you are interested, bilisan mo. dalawa na lang ang available.
gino, thanks for the feedback.