For the October 2009 patch deployment, a few of the patches are not included in our patch bundle, but what we did bring down added up to 1.7GB.
There is also a warning that MS09-056 KB974571 can break LCS\OCS (Thanks to Peter Hunt for passing this info on to me from another of his collegues based in Tokyo)
Not deployed to production yet, so no smoke signals from other teams on anything else breaking.
Read the complete post at http://wmug.co.uk/blogs/r0b/archive/2009/10/14/october-2009-microsoft-security-bulletins-our-pre-deployment.aspx