I have a pair of noise isolating earbuds but you have to hit over the head to get my attention if I have the music above a whisper when I wear them
The M50's are over ear and seal very well so if you are listening at a reasonable volume you can't hear any office noise or people talking unless they are right next to you.
It's a nice balance between complete isolation and people being able to get your attention without waving something in front of you.
They sound great too.
If you're looking for noise isolating then the Etymotic Research HF5's[2] are great. They are earbuds that sound amazing and easily portable.
Both come with appropriate carrying cases.
[1]http://www.amazon.com/Audio-Technica-ATH-M50-Professional-Mo...
Search based on your budget and pick one of the pairs in your range and you will be happy.