ok i have looked through the games and below i have listed the ones which offer value for money with this offer.
KONAMI PRO EVOLUTION 6 XBOX 360 £24.99
MICROSOFT LIVE ARCADE UNPLUGGED XBOX 360 £17.99
CALL OF DUTY 3 XBOX 360 £29.99
CRACKDOWN XBOX 360 PRE ORDER £37.99
GEARS OF WAR COLLECTORS EDITION XBOX 360 £37.99
LOST PLANET LIMITED EDITION XBOX 360 £39.99
there are plenty of games which i wouldnt go for for £19.99 which let you use the offer also, and several preorder games most at £37.99
PC WORLD just incase someone didnt realise.