If you want it now, buy it. The only way Apple will reduce the 64G price is when a new model is introduced. If you look back through the old post, people were stating absolutely the a new iPod Touch (with camera) would be released weeks after the 64g iPod Touch was released. These same people absolutely claimed that a new iPod Touch would be out before Christmas and now they are claiming that it will be in February (since it's almost Christmas).
Nobody knows the real answer except Apple so take anything as a best guess. My best guess is that the updates will be in the normal fall update.
but of course as you said, nobody can be sure but could it really hurt waiting a month and a half?
After you wait 1.5 months and it doesn't come out, people will say to wait another 1.5 months since you are getting nearer the refresh date. People have to make their own decisions on when to buy but, if you only listen to people who say wait to buy, you will never end up buying.