I use Audio Technica ATH-900 - I also work as a programmer and want to drown out the talking, though it's not as bad as your environment. I found they work very well in this regard without compromising sound quality too much. Extremely comfortable. I also have HD-25 II and find those great for portable use - but not comfortable enough to use the whole day. I agree with jawang and believe HD-25 isolate about as good as you can get without active noise cancellation.
By the way there was a very well written (and LONG) PDF document somewhere around here that targeted portable/closed headphone options well. It's probably quite out of date now but it may give you some ideas. That's how I decided to try A-900 which I bought on my trip to Japan, as they'd be hard to get otherwise. The recommendation was spot-on.
Active noise cancellation is definitely something you may want to consider, too.
By the way there was a very well written (and LONG) PDF document somewhere around here that targeted portable/closed headphone options well. It's probably quite out of date now but it may give you some ideas. That's how I decided to try A-900 which I bought on my trip to Japan, as they'd be hard to get otherwise. The recommendation was spot-on.
Active noise cancellation is definitely something you may want to consider, too.










