I have owned this particular model of earphones for over 1.5 years (I checked, I bought them in August 2007 from another retailer!) and would never, ever, hesitate to recommend them.
This is assuming you do buy the *original* earphones and not the equivalent OEM - I remember this was a hot issue back in 2007 and anyone who did complain about the earphones had inadvertently ended up with the OEMs. There should still be sites with photos to help you identify the latter.
I use these on the way to/from work on the bus, on the Tube and when out walking on the street. The noise cancellation is excellent - they are in-ear bud earphones which are very comfortable in my experience - although how much is blocked out is also dependent on the volume of your music! Clearly it's safer to let some sound through when you're crossing the road or listening out for Tube driver announcements, but if you want your own little bubble of music or radio comedy from the BBC, this will be an excellent purchase as it is good value for money and it works just as it says on the tin.
I cannot fault the quality of the sound that comes through the earphones, although it does actually depend a little on the processing engine (or whatever it's called) of your music player. For instance, I have noticed that I definitely get a richer sound from my Sony Ericsson phone than my LG phone.
Durability wise, as with every other commuter, the wire can get caught in the most annoying things (like coat buttons and bag zips when squashed on the Tube) and 1.5 years later, they are still going strong, which I think speaks for itself! One other reviewer mentioned breaking their first pair within the first month, and since I use mine all the time - not necessarily gently since I am a a normal person - I am going to assume they gave it some seriously rough handling which would ruin any set of earphones.
To summarise though: iif you want earphones that will give you that 'bubble of space' when you want it, produces good sound, is durable and doesn't break your bank balance, then I would definitely say "Please consider buying this product." and make sure you get the original version if you do.
p/s: And to fellow commuters who get annoyed by others who blare out their music through their poor quality earphones, and would not like to be labelled as one, from what I've found - if the volume has been turned up and the music has a strong beat, some sound will filter through.
However, if the volume is adequate, the ear-buds will pretty much 'seal' in the music just for your ears only.