Randy Holloway wrote about his vision on Linux and then especially about Linux on the desktop. I disagree with his vision, I think Linux is definitely an option for the desktop at the moment and thus also in the foreseably future. It will become the option for the desktop when Mono is completed. The reason for this is simple: a lot of Windows programs will be written using .NET. If you can run these programs on Linux too, using Mono, what's keeping you on Windows? Perhaps the games. But definitely not the business applications, since the Linux version for spreadsheets, browsers, wordprocessors, emailprograms and other every-day software are solid today, even when compared to Microsoft Office XP.
I've hated Linux and especially its most hardcore supporters, for years. However, you can't have an unbiased vision on what is best for a given company to use as the OS of choice if you are biased yourself. Mono changed me, I really think Mono is the best Linux has ever experienced: it makes transitions of software written for the Windows platform to a free (as in beer, I don't believe in the GPL-philosophy) OS possible.
Besides Mono, I do think Linux is a good platform to use for everyday business applications today, because the office tools can use Exchange, they can read/write MS Office documents, so why bother investing in MS software when you can save that money and choose the alternative? The only problem is: when you have a lot of desktops to admin as a sysadmin, and you want to do that with the easy tools in Windows server 2003, you're out of luck.