Two inches more

Cost of 15″ Macbook Pro: S$4588
Upgrade to 2.16Ghz Intel Core Duo: S$535.50
Upgrade from 100MB to 120MB hard disk: S$178.50
Total cost: S$5302.
Cost of 17″ Macbook Pro at 2.16GHz Intel Core Duo with 120MB hard disk: S$4988.
It has Firewire 800, which the 15″ model doesn’t have, 8x double-layer SuperDrive (as opposed to 4x) and an extra USB port.
Go figure. Is it simply a case of paying less for more bulk? Will there be a price drop for the 15″ model?
Whatever the case, I think I’ll hold out until OS 10.5 arrives.