People say a £2 hdmi lead is no different to a £20 or £50 lead.. Thats wrong.. the difference is Quality! A cheap lead wont last as long as say a more expensive one.
I've bought 3 cheap hdmi cables costing less than £1.50 and 1 costly (imo for what it is) £13.99 3D capable hdmi cable (for my ps3). My 3rd cheap one is on its way out 2 months of use and im getting black screens flashing during gameplay.
So in future spend on quality, your xbox deserves it.