What 7850 is best out of all the ones that are available? The prices range from £140-180 so I will only spend £170 on a card.
http://www.overclockers.co.uk/productlist.php?groupid=701&catid=56&subid=411
http://www.overclockers.co.uk/productlist.php?groupid=701&catid=56&subid=411