Linux may be a good fit (and save a bundle of money)
in these roles:
Server: file, MySQL database, webserver, print, email, fax, firewall, and authentication services
Desktop: web browsing, email, office applications (word processing, spreadsheet, database, presentation graphics are included in Open Office), MySQL database, and graphics design
I support several versions of Linux, including SuSE Linux, CentOS Linux (very similar to Red Hat Enterprise Server Edition Linux), and Ubuntu Linux (similar to Debian Linux). These are all Open Source distributions of the GNU/Linux operating system.
Why deploy Linux servers?
1. Avoid paying "the Microsoft tax". No initial cost, no client access license fees, and no update purchase costs. Independent authorities agree that the total cost of ownership (TCO) of 100% Microsoft networks exceeds the TCO of networks with Linux servers -- and the cost gap widens as your network grows.
2. Enjoy system stability
3. Improve resistance to virus infections of servers
Ubuntu desktop. This is a popular desktop operating system, with tens of thousands of application programs available.
How steep is the user learning curve?
Today's Linux desktop will feel familiar to users of both Windows and Mac operating systems. The keyboard and mouse work the same. The desktop is similar. (It differs just enough to avoid copyright infringement).
How about “under the hood”?
The underlying directory names are substantially different than Microsoft Windows' directories, but most business users won't be concerned with these details. To them, most applications will work as expected. (The Mac OSX file structure is a Linux file structure.)
More Cost Advantages
Linux, unlike Microsoft Windows, will run nicely on older hardware. There's no need to scrap perfectly good computers just because Microsoft releases a new version of Windows.
Open Source software isn't restricted by commercial licenses: users can have multiple PCs with the same software installed: at work, at home, and on the road.
Open Source software frees management from the burden of monitoring proprietary software usage -- and from the very real threat of legal prosecution if such monitoring should fail.