This is the scenario I believe is going to play out:
This week Apple will drop the price on the PB's by $200 to stimulate sales before MWSF.
I could see this, if you add a speed bump to 800/933 (and maybe a Radeon 9000) to the update this week. Just dropping prices on current models by $200 isn't a very compelling update; I've been waiting a while for this update. If there's a decent speedbump, I'll buy (even without the price cut). But if there's no speed bump, I'll hold off until January.