Tesco Direct have the XBOX 360 and PS3 versions of Modern Warfare 3 Hardened priced at £75.
Using the code TDX-MNGK you get £10 off a £75 spend. Tesco Direct charge £5 delivery so if you arrange to pick up from store its only £65 but delivered will cost you £70.
Not sure if you can get Quidco or topcash back so dont forget that as well! You also get 150 clubcard points :)
Seems to be the best price for the Hardened version at the moment!
Link to ps3 version: http://direct.tesco.com/q/R.213-1414.aspx
Extra info on what ELITE contains: http://www.callofduty.com/elite/whats-included.html