Microsoft are starting to have problems with Vista/Office 2007 already - they have had to add Open Document Format support to Office 2007 at the request of governments and large corporations (only read support so far I think) and it is not released. In late 2005 a Microosft exec stated that to effectively run Vista and Office with all the bells you would need 2 GB of RAM, SATA-II HDD, dedicated graphics card with 256 MB memory and he didn't mention having any other applications running. Recent costings with these specs put the system at $2500+ in Australia without Office (assuming Vista is the same price as XP Pro).
Not many businesses can afford to have $2500 tied up on systems doing Internet, e-mail, word processing and spreadsheets, which is all most office systems do really
, so cheaper alternatives with these features become more attractive all the time. The current versions of Apple's iMacs are also looking good for these tasks with better multimedia support and security (due to the FreeBSD background) and with Bootcamp making the installation of Windows easy market share will increase.
IMHO, Linux needs a single place to configure installed components, preferably with a GUI interface, to make skills truly transferable between distributions. I use OpenSUSE with YaST which makes a great start but really it needs to be much more "intelligent" - if I don't have a DNS server installed why do I need the configuration icon.