I would go for the OCZ Gold 6GB, it offers the best price/performance:
http://www.overclockers.co.uk/showproduct.php?prodid=MY-153-OC&groupid=701&catid=8&subcat=1392
Also OCZ Reaper 6GB is great value too:
http://www.overclockers.co.uk/showproduct.php?prodid=MY-136-OC&groupid=701&catid=8&subcat=1391
With the more expensive memory I'm not convinced you'd notice much difference - only to your wallet![]()
I think you shouly get some new SSD's, and give the old ones to me!