I agree with your statements.
Since the 256 mb card is about $100.00 higher than the 128mb version, I can't see what the advantage would be with the games we have at present and coming this year.
The game writers are certainly not going to write a new game IE:

oom3 and make it to not run in most of the systems we are using at present. Doom 3, Half Life 2 and the such will run on the Radeon 9500's as well as the 9800 line without going to the 256mb card.
The only advantage of the 256mb card would be in CAD work or photo editing, the 256mb version may be a great appliance in that arena.