i would definately vote for Greek Food.
Tasty unlike the italian, well grilled unlike the French and Meditereanian unlike Spanish.
you wont find cheaper and in the same time, good quality.
An average cost per plate is about 20-25 euros(Thats about 17 pounds)
I would say the best food destination would be either Hong Kong or Singapore, because they have the best of both Western and Asian food choices in various price points.