I'm currently living in a big city, and working in an open-plan,
so I wanted a nice headphone to cancel the ambiant noise
enjoy my music, but the plot twist is that I still need to hear when my
colleagues are yelling at me because I broke something on production
kindly speaking to me. It would also be nice if it could be small.
To sum up, I was looking for a headphone:
- with active noise cancellation (also known as ANC), to be able to work in silence, and to refrain my desire to bomb the public transportations system everytime I'm using it;
- small enough to be carried away everywhere without taking all the place in my bag;
- with a sound as neutral as possible: I don't like when my audio equipment is tweaking stuff on its own;
- that could still be usable with an empty battery (if it comes with one).
Bose is known to be the go-to player when it comes to ANC, with their QuitComfort 25, unfortunately, 300EUR is super-expensive, the sound is way too warm for me (Classical music and metal tend to sound groovy with it.), and it was a bit too bulky to match the "please don't fill my bag" criteria.
I then tried the Plantronics BackBeat Pro, because of their nice review on les numériques but despite being way cheaper (150EUR) and with a lot of fun features (like pausing the music and activating the ANC upon phone calls ♥), it was way too big (and heavy!) to wear all day-long.

I finally gave a try to the n60 from AKG, a small, foldable headphone, with active-noise cancellation, for less than 200EUR: love at first sight! Sufficiently small to be carried in my pocket, lightweight (150g) enough to be forgotten once wore, comfortable even for a glass-bearer like me, its sound is super-precise: you'll hear when a track is ill-mixed, the battery for the ANC leasts at least 30 hours (you can still use it when the battery is empty), …
A minor downside is that the ANC produces a small distortion, but every headphone that I tried had one, and it's strictly better than having to endure the noise around you.
I have mine since a bit more than a year, using it on a daily basis, 9 hours a day, and it's still looking brand new: not a single scratch, no vanishing foam, even the cable looks great. I wholeheartedly recommend it.
edit (2018-06-30): The cord got a bad contact, cutting all the mediums,
so I had to buy a new one. Careful, it's a jack 3.5 to 2.5, with 4 stripes,
not the usual 3 ones.