Any of these.
http://www.overclockers.co.uk/showproduct.php?prodid=MY-307-CS&groupid=701&catid=8&subcat=1517
http://www.overclockers.co.uk/showproduct.php?prodid=MY-290-CS&groupid=701&catid=8&subcat=1517
http://www.overclockers.co.uk/showproduct.php?prodid=MY-132-CR&groupid=701&catid=8&subcat=1517
Or this, but not on offer.
http://www.overclockers.co.uk/showproduct.php?prodid=MY-094-KS&groupid=701&catid=8&subcat=1517
the 2 corsair ones are the same spec, are the cheapest and the fastest/tightest, the only difference between the 2 is the colour of the heatspreader