Today is stone silent with the exception of the FOMC-related events, which are not only the most significant events of the week, but of the month as well.  Today's FOMC is more important than the last few for several reasons, not the least of which being the generally higher percentage of market participants that seem to be expecting at least something other than a status quo statement.

But while a good measure of today's importance rests on relatively more recent market information, a portion of its cachet is owed to it being the last scheduled opportunity for the Fed to communicate policy before the expiration of the current "twisty" intervention.  The ongoing nature of Twist gave the Fed an opportunity to simply state that "the plan goes ahead as... planned."  

Expectations evolved into speculation on whether or not the Fed would start tightening policy and the reassertion of Twist buying was almost a way for the Fed to come across as "more dovish" or providing "more stimulus" even though they were merely sticking to the schedule.  And that's really why today is so big, or rather, COULD be so big.  Not only does this happen to be the meeting at which new action must be decided or foregone, but it coincides with a particularly nasty bout of Euro-drama as well as a potentially disconcerting pull-back in the tenor of domestic economic data.

We'd imagine (and this is more of a guess than any sort of scientific survey) that the average market participant views the baseline policy statement today coming in the form of a Twist extension.  In other words, if the Fed does something or suggests the impending future probability of something above and beyond merely lengthening the time Frame of Twist, that would be on the dovish side (aka: more agreeable to easing).  Bond markets would likely approve, especially if the "above and beyond" part includes any specific reference to MBS.  

On the other side of the coin, if the Fed can manage to not AT LEAST extend Twist (or offer something in its place), that would be the more hawkish stance, likely taking a great many by surprise, and creating a potentially painful knee-jerk to the weak side for bond markets unless accompanied by some clever means of softening the blow (which might look like an actual mention of QE3 readiness and vigilant monitoring of the current situation).