A couple of years ago  I decided that I was going to by myself some fancy headphones to accompany the new Hi-Fi I bought in the previous year.  I kind of set my budget at about 70GBP for what I thought would buy me a great pair.  I had researched some cans at about that budget but I didn't want to buy without listening or testing for comfortability (me clever),  so I refrained from purchasing.  Later that year I had my some hols in Japan and as a tourist I visited Akihabara, Tokyo where the electronic stores are.  One shop called Yamada was about 6 stories high each floor contain different electronics (like a dixons store but multiplied by 6), on one floor the HiFi section was located, and on on wall was end to end headphones all set up for demonstration.

I tried every on every pair from budget Sennheisers through to a pair of "AKG K1000 reference" costing 1500pounds.
(you will need to copy and paste due to ebay restrictions: www.audioreview.com/channels/audioreview/images/products/product_125815.jpg)
I know I wasn't going to purchase them but I needed a benchmark.  For the years of hype I was looking towards Sennheiser, but wanted to compare them to Grado and (more Japanese based brands like) Audio Technica.

To be honest I wasn't really impressed by them so I decided not to purchase any.  However near to the odd shaped AKG's were another brand that looked similar, it was clear where AKG had stolen their design from.  I tried them and they were amazing.  I checked the price, about 350pounds but no way I was going to pay that...

(you will need to copy and paste due to ebay restrictions: www.stax.co.jp/JPG/3010/SRS3010s.jpg)
Hearing the Stax SRS3010s (SR-202 ear-speakers + SRM-310 amp) headphones opened my ears to the appreciation of headphones, everything was so delicate and airy.  Suddenly I realised that if I had spent 300 quid on main speakers for my Hi-Fi I really had to spend 300 quid on headphones to get the same quality of sound.  The SRS3010s was in my opinion the best sound despite being solid-state (other amps were valve powered) and being at the lower end of price scale.

I was sure I would get them cheaper from a HiFi store in the UK.  How wrong was I?  Turns out the brand is Japanese so availability here is virtually none, so I have never found the exact pair in the UK since and the price for the range here is virtually double of the Japanese price.   Not buying them in Japan was one of my worst shopping mistakes.