I first used an X-terminal in a computer lab in the early 1990's. I was an instant convert. The screens were only monochrome, but they were 21", which was amazing, compared to the usual 12" screens that most people had. But what was really amazing about the computers, was that no matter which terminal I logged into, I had complete access to all my files and all my programs. And I was connected to a very powerful sun server that could crunch numbers faster than any desktop machine I had ever used. As I moved into the windows world I was never satisfied with having my files only on the one computer. Sure, I could save the files to a network drive, too, but then which file was the up-to-date file? And even if I access the file from another desktop machine, there is no guarantee that the software will be installed on that machine, which means having to purchase another copy of the software.
As a concept, I am going to get a higher end raspberry pi, print out a vesa mounted case and mount it to the back of a monitor. At that point I am going to configure the raspi to connect to my main linux server using XDMCP using the instructions here: http://tldp.org/HOWTO/XDMCP-HOWTO
It would also be possible to go full Linux Terminal Server Project (LTSP) and have a raspi boot into that framework, they are working on that here: http://elinux.org/RPi_Projects
I am more interested in configuring the raspi to connect as an X-terminal to my main server. Monitors are dirt cheap now, and so is the raspi, so combining the two of them together and having them connect to a very powerful back end server is a powerful solution for both home and business.
X-terminals take almost no maintenance and you could replace the entire raspi setup for just $25. A 20 inch monitor is just $110. Throw in a keyboard and mouse for about $15 and you can put a complete computer in for just $160 a seat. A 26" monitor would just add $60 per seat.
Instead of spending $600 a seat on 10 desktop computers and a couple of thousand dollars on a server, you can spend $1600 on the computers, and then build an amazingly powerful main server with part of the $6,400 you would have spend on the weak desktop machines and weak server in the first scenario. This main server will be much faster than any desktop machine. Dual quad core with 32 GB of ram, mirrored raid drives.
The x-terminals would be on their own network that only connects to the main server. No anti-viruses needed per seat. Maintenance is easy. If the terminal is down, just swap it out with a different one. Until the terminal is replaced, all a user has to do is to log into any other computer and have full access to all their software and files. You could even deploy a terminal into someone's home and have it connect into the company securely though the firewall using a Virtual Private Network (VPN), so even that client would only exist on the client network and be completely secure.
Because all the files are in a central location, backing them up is easy. I prefer using rbackup. It creates a full backup, and then incrementally backs up every user file every hour. It has directories that each look like they contain a full backup at that hour, saving disk space by hard linking back to all the files that haven't changed since the last backup. It is easy to put a link on each users desktop that directs them to the last backup, or to their backup directory
If users have software that only runs on Windows it is trivially easy to run a single multi-user windows server and connect into that box using citrix to put the window app right onto their x-terminal screen. This is built into windows server which provides Remote Desktop Services, in a similar way that X-windows works : http://blogs.technet.com/b/windowsserver/archive/2012/05/09/windows-server-2012-remote-desktop-services-rds.aspx You can install anti-virus, anti-spyware, and all that on the windows box to keep it protected, and physically firewall all access to the windows box to keep it from being infected and taken over by worms and viruses. And you can mount the directories from the unix server to their home directories on the windows side so that they have full access to all their files on either the Windows side, or the Linux side of things.
I'd do all my print queues and mail through the Linux server, because it is just so much easier to maintain and more reliable. Where ever possible, switch to free and open software, this is one of many links that describes 75 solutions to replace expensive, unreliable windows software: http://www.datamation.com/osrc/article.php/3877196/75-Open-Source-Tools-to-Replace-Apps-You-Use-Every-Day.htm
You can wean people over to open source software on windows first, and then when they find the same tools available on Linux, they will spend more time working with the identical apps there.
Why would a business change in this way? Because your competitors are all using Linux and Open Source more and more everyday. And unless you work continuously to reduce every cost in your company, another company will, and will drive you out of business. Using open source software effectively provides a competitive advantage over those who do not.
You can reduce administrative costs, effectively eliminate desktop support costs, provide your employees with robust access to their data files and programs, all while improving their productivity by giving them access to a server that is much more powerful than you could otherwise afford.