I keep forgetting to check this site, so I sometimes miss out on replies :)
I won't completely discount Linux as a solution, although as I mentioned I doubt that management will want to get rid of their "investment". I'm not certain about this company, but in my past experiences once the company has spent money on something (in our case it was a $6,000 license for MS SQL Server), they don't want to "throw it away" by moving to a platform where it wouldn't function anymore (i.e. If we convert our servers to Linux).
or_josh, you're right in that I'm making the error of thinking a move to Linux has to be done in one fell swoop. I'm new to being in the "Director" level position (although it's not a "real" director position as I don't have direct reports) and being able to recommend solutions/upgrades/etc. so I tend to jump the gun a little and think in broad, sweeping changes instead of starting small. In a pinch we could even keep the desktops running XP for now (moving Office -> OpenOffice) and use Linux on the servers, and move the clients to them at a later date :)
Anyways, it's something I will bring up if I get the chance to discuss future options with management, as an alternative to spending close to $20,000 (over three years, granted, but still) on getting the required MS licenses. Although, from what I've seen (and I admit I didn't look 100% into it), going with a Linux provider (let's say Novell/SuSE, since I'm not a fan of RedHat) still has a yearly or monthly charge, if you want support (which, for a business, I'd certainly want). As I recall, the price was only slightly less than the cost of Windows (although less licensing restrictions, I admit); it was still about a hundred bucks or so per computer, per month or year (I forget which). To management, that looks like a bigger cost because, technically speaking, once you pay the fees for using/licensing Windows, that's it. You don't have to keep paying Microsoft unless you upgrade the software, and even then it's usually a one-time charge for a couple of years. Linux seems like it's more of a cost (although it's not) because it's a recurring charge. Although, I suppose my experience has been flawed because I've normally worked for very tight-fisted companies who hated spending any money at all, and actually have had subscription charges refused because they didn't like the idea of having that much money (I forget the details and the price) be automatically recurring.
In any event, I'll keep it as an option. Thanks again. Happy holidays to all!
