Microsoft will release a huge security patch tomorrow October 13th containing eight critical and five important security bulletins fixing 34 vulnerabilities.
Affected software includes Windows, Internet Explorer, Office, Silverlight, Forefront, Developer Tools, and SQL Server.
Windows 7 is also affected by this monster patch fixing a critical IE 8 bug and two important marked issues found in the Operating System. Windows 7's release is still 10 days away. So you will already have a security update waiting for your new Windows 7 computer when you get it. The patch will be downloaded automatically as usual if you have set your Security Center that way. A restart of your system is most likely required after the update.
More details in this Microsoft Bulletin and in this Technet post.