Thats a decent enough start point for a good gamnig rig really.. tho you could maybe get a slightly cheaper mobo one for around £100 will still do all you need you could put that extra cash into the graphics card then.
Somthing like this for the mobo.
http://www.overclockers.co.uk/showpr...=5&subcat=2574
Didnt realise those Haswells where so cheap. You may as well stick with that I guess.
With that £50 you save on the mobo you could try and save a bit more as well and get this card.
http://www.overclockers.co.uk/showpr...14&subcat=2294
As for the OS your right that will bump the price up a bit as well so maybe the better graphics card is not an option..
http://www.overclockers.co.uk/showpr...odid=SW-152-MS