Check out this excellent article on Desktop Linux. It's essentially unbiased - the author is obviously supportive of Linux (specifically Ubuntu) as better than Windows, but he still admits where Linux is not yet ready for the desktop - file compatibility with Microsoft Office file formats. This of course, is entirely due to Microsoft, and as more people move away from the closed "standards" to the international ISO standards such as ODF, this is getting top be less of an issue.
Anyway, this is an excellent article for anyone to read, whether you are happy with Windows or not (and who is happy with Windows?) Just remember that besides Ubuntu, there is also SuSE, which offers excellent Windows compatability, as well as enterprise support and server editions.
Running a business on desktop Linux