Windows Vista is best left alone until Service Pack one is released, and someone has done a full registry hack to disable the Digital Rights Management stuff. And all the chatting it does to Microsoft on a regular basis. New security features are annoying as they encourage you not to use the Administrators account, but loging in as a normal user can leave you clicking OK a lot as the OS prompts you to make sure you want to install software, upgrade drivers etc. It's not just one prompt, it's many!
As for Office 2007, Microsoft are trying to give it away in the US to get it adopted. The main problem is the default 2007 Microsoft Office file format is new, and incompatible with all previous versions of Microsoft Office. You can save as, but forget to do it and send it via e-mail then the recipient has to have Office 2007 as well. There is not yet an Office Compatibility Pack available for Office for Mac. There are also formatting issues between versions.
Rule number 1 of Microsoft Software
NEVER INSTALL UNTIL THE FIRST SERVICE PACK IS AVAILABLE(As a minimum).
(That's one big nerdy rant

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