Nope, no noise cancellation on Grados, and they're all "open" design, so they let plenty of noise in. I really like mine, and they're fairly portable (they store flat). I think they're decently comfortable, but they are not known for comfort.
But probably not what you're looking for.
I use Sennheiser HD280s when I want sealed headphones. They're well built and block noise quite well, and sound decent, but they're not especially light and portable, and apply a good deal of force to the head (which helps the seal, but may not appeal to everyone).
Headroom (headphone.com) has a bit of audio snake oil floating around their site, but they have spot-on advice regarding headphones for various uses and price ranges.
