The price of a 15.4 inch with a 2.16 in the UK with a 5,400rpm hard drive is the same price as the 17 inch MBP and you are also getting some extra things with the 17 inch with the extra screen size, double layer dvd, hard drive size/speed, firewire capacity and the extra USB port.
A 17 inch is to big for me and I am still happy with my 15.4 inch MBP. Come Autumn though i think that i may contemplate getting a new MBP and selling my old one if one with the Merom chip comes out by then.