Linux = fail
You will never see wholesale deployments of Linux in major organizations, because, despite its flaws MS is Quick, stable, and scalable
I am working within the animation industry industry at the moment, and a lot of smaller studios have *nix boxes for their rendering, but everything else is PC, and Mac.
What I am seeing now, is Mac is losing ground to PC, because Mac opensource solutions to problems, suck.
Samba can't do anything near what AD can, So I am seeing shops move to AD servers and file servers, because, they do the job, and I can install them in 2 hrs.
With a *nix box, its 2 hrs of install + 8+ hrs or bugs, kernel recompiles, strange issues, driver hunting, hacking, kicking, screaming.
Not to mention all the app compatibily issues. If you wanted to run a *nix solution in a large or medium business, then you need to retest and re write a whole mess of apps. The business case AGAINST spending that money is HUGE. You spend half the money on a decient BOFH, and have solid stable network.
When they are paying me to be there by the hour, open source just looses on the numbers game. Any gain in no cost software, is lost with support time.
Government deployments don't count, because government departments have HUGE budgets for stuff like this, and never have to worry about being profitible. They can spend all they like on app writing, testing and creation.
I hate MS's buggy, ugly OS as much as the next man, but from a BUSINESS point of view, MS is a better choice.
If a better option comes up, then I will reccomend it. I have quiet optimism for Google OS, but I will see what she looks like, with the lights on first.