It is a lot of money I agree, but what you get is studio quality headphones that will last a lifetime and you'll never need to upgrade from them. If you spend £60 every 2-3 years (headphones in that price range break after a few years heavy use) you'll spend more money overall than if you buy the Beyers which have metal in all the stress points where headphones break. If you buy them from Amazon you can try them for a week and return them for a refund if you don't think they are worth the money; what have you got to lose?
I'll be completely honest with you and say get the Beyerdynamic DT770 headphones and buy my Xonar DG. Up until you've another £130 odd to spend you won't get a decent headphone amp and DAC and you'll notice more of an improvement buying a good pair of cans and a cheap sound card over a lesser pair and a good amp and DAC.