I have the Shure SE530s and they blow away anything else I've ever owned. I used to be in the noise canceling camp (my first NC earbuds, a pair of Sony MDR-NC10s, lasted 10 years and are still good, but I retired them) but sound isolation is the way to go.

The SE530 is pricy but if you can stretch your budget a bit I think it's a really amazing product. Shure also offers a full range of products, including several in your stated budget range, some of which are discussed in this thread:

http://www.flyertalk.com/forum/trave...g-earbuds.html