If all I wanted was a phone I could get a N1661 which weighs 100g less than the N900, although this is offset somewhat by the weight of all the cash I would still have in my pocket.

Being old, I remember the original Motorola cell phone which weighed nearly 800g. Carrying 400g and even holding it to my ear does not seem to be that big a problem given the offsetting benefit of a bigger screen and keyboard. Besides, with Bluetooth headsets, I don't need to take my phone out to answer calls.