Hi,
I have the Etymotic Research ER-4S earphones. They were very pricey ($300 at
www.headphone.com), but worth it IMHO. I use them at work in my cubicle, and they effectively block out the chatter. I find that I can listen to music at a much lower volume since there is little noise that comes through the 20-25db noise isolation. On the other hand, I can still hear my phone ring, so that's good. They will certainly work better than any active noise reduction headset.
Etymotic offers three models you can consider: the ER-4S, ER-4P, and ER-6. The ER-6 is not quite as good as the ER-4, but it's still excellent. It offers slightly less noise isolation. It costs quite a bit less. The ER-4S has the best sound, but you need sufficient power to drive it properly. The typical CD portable may not be able to drive the ER-4S well without the assistance of a headphone amplifier. At my desk, my PC's sound card is too weak for the ER-4S. I am currently using a Stereo-Link (
www.stereo-link.com) USB external sound processor that has a good headphone amplifier built in, and it's great. There is also the ER-4P, which is nearly as good as the ER-4P (same cost), but requires less power to drive. This one was designed for underpowered portable audio devices.
Note that Etys will not exhibit bloated bass like 95% of the mass market headphones. The Etys offer very flat frequency response without any mid bass hump. It may take a little get used to hearing "real bass" vs "bloated bass".
Also, there are two tips options: plastic and foam. It takes some practice, but a lot of people have had success getting the plastic tips to seal properly and comfortably. For myself, I prefer the foam tips.
For more information, check out the Head-Fi forums at
www.head-fi.org. Lots of Ety fans there.
Good luck!