Saving money by the boatloads because while you're not invulnerable to anything, you reduce the risk factor by a huge amount and hence, save yourself, your company, your IT staff, and whoever else the stress of the numerous zero-day exploits coming out that affect said targeted OS/applications.
I only partially agree. In theory I agree, but that would be in a perfect test world somewhere.

In reality, ignorant and irresponsible users will still be ignorant and irresponsible users. The biggest reason Linux is more secure for those of us on AO is because we know what we're doing. With Linux-novice admins and Linux-novice users it would take a while to reverse that "inertia" mentioned earlier and get to the point where everyone was comfortable enough with Linux and understood how to configure, administer and use it properly to see the fruits of those labors.

I honestly think that if you unleash 5,000 employees used to using Windows onto Fedora desktop machines they can find a whole plethora of ways to break it that Linux gurus haven't even thought of. I also believe that good network and perimeter security is good network and perimeter security and if the fundamental network infrastructure were configured and secured properly issues on the internal workstations would not have the impact they do now.

I will grant you that current attacks and malware predominantly target Microsoft, but just let a major corporations, especially banks and financial institutions, swap their infrastructure over to Linux and see how long it takes for malware and attacks to target the multitude of flaws and holes in that system as well.

I am not saying I think Windows is cheaper in the long run and I am not saying I think Linux is inherently secure. I am saying that the debate is not as black and white as Linux gurus would have you believe. There are many more factors that play into the decision both short and long term.