had my Five since 2009 and its always been the rear mech hanger needing a bit of lube on the screws or the rear wheel QR needing clealing and a bit of lube
a few months ago a proper crazy creak started and would not stop
did the normal stuff and also cleaned and lubed anything with a thread and still it was there
in the end I took a gamble and got a BT Swiss thru bolt and a couple of new caps for the hope rear hub
not a peep out of it since
the bike has never been so quiet
think it cost me about £30 to £35 for all the bits
deffo worth thinking about or just try a QR off another bike
http://www.chainreactioncycles.com/dt-swiss-rws-thru-bolt-alloy/rp-prod81162