In its article: Hands-On with Windows Vista Service Pack 1, PC World says:
Microsoft’s first service pack for Windows Vista focuses on stability and security.
The first service pack for Microsoft’s Windows Vista operating system won’t arrive until early next year, but judging from our experience with a beta of SP1, the update will be more about stability and security fixes than noticeable performance gains.
It is obvious that Microsoft works hard on security and tries to overcome bad public opinion about Windows family of operating systems. Poll on this blog shows that, at moment, opinion about Windows OS family security is still unsatisfactory even of Microsoft’s big effort to improve and make better. Look at right upper corner and also at Polls archive. You can vote for your favorites in this poll up to end of January 2008.
Windows family is the widest used OS and it is expected that, something what is in common use, will be more exposed to attacks and therefore subject of increased analysis and critics.