Probably not very many people are surprised, but Vista has been hacked. Microsoft issued a challenge to hackers at the Black Hat security conference and Vista was hacked in a demonstration at the conference in Las Vegas, Nevada.
A researcher by the name of Joanna Rutkowska show it was possible to bypass Vista security measures that are suppose to prevent unsigned code from running.
She also explained how to use virtualisation technology to make malicious code undetectable. Rutkowska code-named her malicious software Blue Pill.
Microsoft said it is working on solutions to prevent the attacks Joanna Rutkowska demonstrated before the final release of Windows Vista.
There is a lot more information related to this. I've linked to an article with those details
Vista hacked at Black Hat: News - Security - ZDNet Australia