Some new thoughts for this thread. I just flogged my Grado SR125s (meh) and bought a new pair of 'phones for home use with my FiiO E7 and E9 combo (Beyerdynamic DT880s), and as I have no sense of thrift or restraint I decided to get ANOTHER new pair, for travelling, while I was at it. Horses for courses indeed. I had the same issue as the OP that I was using a very decent pair of Beyerdynamic MMX101 IEMs (with my trusty iPod Classic/FiiO E7 combo) for travelling, and I'd started to get a bit fed up of my ears feeling genuinely violated after prolonged usage. I was also using Comply foam tips, and was finding that, quite aside from the violation issue, isolation wasn't good enough for tube journeys where I would basically only be able to listen to constantly loud music - pretty useless to me as I'm a classical musician, and as such listen to a lot of classical music and do a lot of travelling, especially within London.
After a bit of digging around and pondering, I thought that I'd probably go with a simple pair of closed-back headphones which would have passive isolation but without the complete death of sound which I've previously found to go along with N/C headphones. I'm afraid the Bose QC15s are the culprit for my prejudice there, I just hated how they sounded on the couple of brief occasions I've tried them - not exactly either a fair or original comment but bah, they are SO expensive and sounded SO mediocre. I was looking in the sub £150 price bracket, preferably sub £100, and I was ready to pull the trigger on a pair of AKG K550s from Amazon at £99 when I thought 'why don't I buy them from a real shop?!' and so checked the price on Richer Sounds. Lo and behold, same price, and in the store I was going to (Holborn) they also had a pair of Harman Cardon CLs open box going for about £60, which I thought it would be nice to try.
As it happened, they couldn't find the Harman Cardons, and didn't have any open box AKGs - bummer. However, I spent long enough hanging around and trying out all of the cans they did have open that they eventually very kindly agreed to open up a box of AKGs for me, so I had a chance to try out a few pairs, with commuting (especially tube/train travel) in mind. In the end I tried:
AKG Y40 (£69.95)
AKG Y50 (£79.95)
AKG K490NC (£139.95)
AKG K550 (£99)
Goldring NS1000 (£69.95)
Sennheiser Momentum (on-ear) (£129.95)
(Sennheiser HD25) (£99.95)
All through the iPod Classic/FiiO E7 combo, running Apple Lossless files (sadly for most people all classical - Beethoven Symphony No. 5, Bartok Concerto for Orchestra and Stravinsky The Rite of Spring and Symphony of Psalms). I spent a good while in the shop, but obviously this comparison is limited to first impressions of demo models (the K550s were fresh out of the box, everything else had been sat on the wall for who knows how long). The HD25s were broken and only one ear worked, so they can't really be counted. The Momentums had a pretty nice sound signature if you're into the Sennheiser vibe (it seems to be pretty bass-heavy and I found that with these), and I definitely didn't hate them. I would personally have preferred something a bit more neutral, although I would be interested to try the over-ear ones - the on-ear design didn't provide enough isolation to consider them for my purposes. I'd expected that, really, but you never know. The AKG family was very interesting - all on-ear design apart from the K550s. I tried the Y50s first and was not particularly captivated - it was a fairly grey and uninvolving sound, with not a huge amount of detail retrieval or much depth to the sound. Then tried the Y40s, which sounded considerably worse (not surprising at £10 cheaper). I then took the unexpected plunge into N/C with the K490s. The N/C seemed pretty useless here, to be honest. They're also on-ear (like the Y40s/50s), and the lack of a clean seal probably didn't help the technology, and ambient noise was still very present even with the N/C on - with it off they barely provide any isolation. However, the sound was much more involving than either of the little brothers (again unsurprising) and along with the Momentums was the best I'd tried so far. They seemed to have a much tighter presentation, with pretty decent detail retrieval and a fairly neutral signature (although I would have needed to try them for longer to really judge). On a whim, I then got down the Goldrings to see what the other N/C headphones in the store could do. This was the day's big surprise - the N/C was terrific. Along much the same 'witchcraft' lines as the Bose QC15s, I was really impressed with how much ambient noise was immediately filtered out as soon as I turned them on. They're over-ear, and have comfy leather pads which provided a good seal around my ears (which aren't particularly small - I've since seen reviews mentioning that they might not fit all ears but I found them very comfortable on a large head and fairly large ears). The sound wasn't exactly gripping at first glance, but the simple fact was that I could hear the music clearly despite the considerable amount of traffic noise coming in through the door and music in the shop. Evidently I had just been an idiot about N/C. It makes a big-ass difference. So I tried the Goldrings up against the K550s in their demo room (and was back-referencing my Beyer IEMs as well), and I have to say that the Goldrings kind of held their own. The AKGs clearly have a more engaging, revealing and classier presentation, but not by so much as I expected. The K550s lost out on a number of practical points - there's no detachable cable, the isolation is poor both ways (they let in a lot of ambient noise and are quite leaky) and the cable is also really, really long (seemingly small issue, but when you're plugging it into your pocket, there's not all that much space). So I took much the same decision as the OP, and bought the Goldrings. The difference is that my pair of really effective N/Cs with mediocre sound cost me £70, compared with god knows how much for those Bose badboys.
For a bit more detail on the Goldrings - I EQd the bass up on my FiiO and discovered that they actually have more to offer than I first thought, which was a bit of a bonus really. The level of detail retrieval smashed the others I tried today out of the park (except the Momentums and the K550s, which cost twice as much and aren't N/C), and I really enjoyed listening to a number of pieces on the way home. They also have a fairly clean presentation across the register, once I'd injected a bit of warmth via the FiiO. The only area they are really lacking at the moment is the high mid/low treble area - strings lose a lot of colour in that register. High treble is also a little bit suspect; there's a sort of over-crisp sound on snare drums and very high strings. Brass has a lovely bright and forward presentation, but lacks a bit of shine (improved by the added bass) and listening to Shostakovich's 2nd Piano Concerto the keyboard sounded really excellent, with a very realistic softness of touch combined with nice crisp articulation. They're also very comfortable, have a detachable cable which could be upgraded and look pretty nice. The build quality isn't top, but they feel like they won't fall apart tomorrow (fingers crossed...) and the battery compartment is really convenient and takes a regular AAA battery. All in all, I think they are a total bargain at £69.95 in store (and probably cheaper elsewhere online).
In true OP style, I've rambled enormously here, but my point is that I totally agree with the gist of this thread about different cans for different purposes, and I think that's useful for anybody new to this site - I will continue to use my Beyer IEMs for particularly quiet environments as they just have a more convincing presentation without needing to inject bass, but they can't offer the same isolation as the Goldrings. Likewise, I'm not likely to be using either of them much at home when I have my DT880s here, but obviously I wouldn't dream of wearing them walking around Brixton or on the tube (DERRR). The Goldrings were a lovely surprise - I would say they're underrated but I discovered after buying them that they've got the What Hi-Fi seal of approval (or kiss of death, or something), and have received some favourable reviews on here. Nevertheless, I hadn't heard of them, and I think that given what people have been saying, quite rightly, on here about compromising on sound for convenience, comfort and good isolation they are surely a truly excellent pair of cans at their price point. They're clearly better value for money than the Bose - they're about a quarter of the price by my reckoning, and the sound, although not world-beating, is way more than acceptable, it's decent to good (which is probably about as much as can be said of the Bose, by the sounds of it...).
So there you have it, newcomers to headphone buying - you probably need to get at least two pairs, and an amp, to be able to listen in comfort and at decent quality in a variety of scenarios. Erm...sorry! That said, I would happily recommend either the Beyer MMX 101s (or the updated MMX 102s) or my new Goldrings as a pair of starter headphones, as they are perfectly useable in any scenario. Hope this is of some use to someone somewhere...
