Recommend the QC20i (with an iPhone).
I have used the QC25 but found them very bulky. The QC20 pack fits in your pocket and the overall sound and noise reducing quality is just as good (if not better) than the QC25.
I also use them at home to block out any loud "neighbourhood" noise.
The "in-ear" headphones are very comfortable and I even sleep with them when SWMBO's snoring gets too loud.