If refinery capacity is struggling to return to normal as we enter the winter, and imports are rapidly declining, we will have problems with our gasoline inventory.  However, I can envision a scenario where basically all of the refinery capacity affected by Katrina and Rita is running at full capacity by Thanksgiving.  We could see crude stockpiles plummet as it becomes clear that production data has been manipulated.  Before the hurricanes, the world was likely producing closer to 82.5 mb/d than 84 mb/d, and we have now had lengthy periods where at least several hundred kb/d in the Gulf of Mexico was affected by the hurricanes, not to mention that over 1 mb/d  was out for most of this time.  

In my opinion, by the end of the winter we could have a situation where crude stockpiles are far from zero, but low enough that refineries are having trouble getting all the crude they need to run at close to full capacity.  Of course, we have the SPR, but it would make more sense to tap it for short-term disruptions rather than drain it all winter long.  It may be that upcoming times are far worse than any individual disruption could ever be, but in that case it doesn't make much sense to drain the SPR immediately.

If we have consistent crude drawdowns of more than 5 million b/d, the price of crude would likely soar.  Therefore, inventories might not get dangerously low, but only because prices went up dramatically.  That is the job of the free market.  On the other hand, if the price of refined products were to soar in lockstep, the refineries would have no incentive to slow their runs until they absolutely have to.