The mbps and mbs have been updated in October/November regularly (as regular as one can claim), as this is before the Christmas season. Granted, the macbook pros don't have far to go (there's nothing available that's better than SR right now). However, I believe that a simple speed bump (and possibly HD upgrade) could be in order. In addition, something might happen to the 17" display (ie, they might get LED backlights-though this is far-fetched as there hasn't been any word on it).
Summary: If you can wait until January, this is your best bet. Most likely the macbook pros will get a new chipset and possibly other goodies. However, if you anticipate needing the machine by the end of the year, then I suggest you wait until Thanksgiving (Apple hasn't usually upgraded either of the notebook lines after Black Friday-again, usually). As always, if you need it soon, buy it when you need it. There's no point in waiting endlessly if you aren't getting real work done while you wait around.
If you can afford to wait (you don't need the machine soon) then do it. However, with this bump, the mbps might get a whole new look at MacWorld, but may not be available until February. Just keep that in mind.