so many different styles mentioned, obviously looks are highly subjective and peoples personal tastes runs the gamut. I myself have a lot of different tastes when it comes to headphone design.
I notice a lot of people say that regardless of how they sound, people like some of the Beats in terms of their looks & styling. Personally I can't stand any of them - they just look cheap & tacky to me. Like they're trying too hard, and there's virtually no subtlety or maturity in their industrial design.
Sony has always been a leader in product design, one of the pioneers and all-time greats in consumer electronics. I love the classic utilitarian look of the MDR-7506, or something more modern like the MDR-1R (I own both). Many of their older designs are also gorgeous and it's crazy to look at some and then realize they were made in the early 80's, or earlier. Many of them look sleek & modern even today! One example is the DR-Z6 which was previously mentioned in this thread, but there are many others.
Sennheiser's design is a little weird - at first many of their phones did not appeal to me and some even struck me as ugly. But, I do think they put a lot of emphasis on their design and over time you grow to appreciate it. At least they're all unique, distinctive, & original. Maybe not the top of the 'best-looking' list, but I feel deserving of an honorable mention. I think my least favorite would have to be the HD800's which look like something out of Star Wars. I don't know - they just look like "too much" to me… not that they're designed for wearing outside, but I just think I would look / feel silly with those things on my head. I assume the sound is so good it doesn't matter…
I tend to like AKG's style - particularly their new pro flagship, the K812. I haven't seen one in person but they seem to have exquisite precision & detail in their build… I definitely lust after them. Their 'lifestyle' models are also quite nice - I own the K545's and really like the simple modern / minimalist style (and the sound is fantastic, as well).
Shure had the 1840's, and now the 1540's which are my current obsession w/ their carbon-weave cups & Alcantara pads… probably my next purchase.
Another utilitarian model that I love is the Fostex t50rp, (as well as the respective mod's). It's sort of retro, sort of futuristic, rugged, classic, utilitarian… and has those unique sliders that look f'ing cool. A lot of the mod's are also very nice looking.
Fostex also has the TH-600 & TH-900, which are 2 of the absolute sexiest HP's out there today. These are another one that I lust after BIG TIME…
And lastly are the Philips Fidelio X1. I remember the first time I saw them while I was just browsing around on Amazon - i immediately perked up & took notice based on their gorgeous, sexy design, and started researching their sound quality & reviews. I had them added to my wish list and I was lucky enough to be going over it one night when I noticed they had gone on sale for $149.99. I about lost my mind when I saw that - truly couldn't believe they were that low. I was lucky enough to get them and have been so happy since then. Both the sound quality is incredible, and their build, materials & looks are stunning. Pictures look fantastic but I don't think they do them justice. I hope they continue making headphones of this caliber.