A400M: Operational service of the aircraft is credible no sooner than 2012-13.
C-17: Entered service 2001. 7 year lease with an option to extend to 9 years = 2010.
Better get out the cheque book. Wouldn't be surprised to end up paying at least twice the purchase price by the end.
The other question is the cost and practicability of keeping the K flying.