The newer Macs (ie, Intel Macs) can run Windows natively through Bootcamp or through virtualisation systems like Parallels and VMware. Macs can run Microsoft Office 2008 (specifically for Macs). This is not exactly the same as Microsoft Office 2007 for Windows as it doesn't feature Access, Outlook (Entourage instead) or Publisher. It has a different UI to the Windows office too.
But are you trying to compare Mac OS X to Windows, or just Macs in general? Because the latter is not a fair comparison as Windows is an OS, whilst with the former it is irrelevant whether you can run Windows on Macs because that's independent of the OS (apart from through virtualisation).
A lot of software exists for both, like Adobe Creative Suite, Firefox, Audacity, Google Earth, Skype, etc. Game manufacturers are less willing to make Mac OS X versions of their games because of the comparatively low market share that OS X has. There are still tons of games out, just not as many as on Windows. Examples of Windows and OS X compatible games include: Age of Empires, Civilisation IV, Spore, The Sims, Guitar Hero III.
Post edited at 4:28 pm on Sep. 13, 2008 by marshmellowman
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and victorious in war shall be made glorious in peace.