System uniformity is something that, if you can plan for it, makes administration and compatibility a much easier subject in your technology plan.
In our Hays office last spring we upgraded all new computer systems there. We waited a year longer than initially planned, but that was so we could save up and replace everything the best we could to be completely uniform.
First off, for the set up, if all the computer systems are identical then you only need to install your base software on one computer and then you can simply image it over to the other computers. In our case, since we built four new computers, that saved me nearly three times the amount of setup time. Sure you still have some final settings and installation after that, but it saves many many hours.
If one computer in their office has an issue, and we are able to find the tool or solution that fixes it, then we know that solution should work on every computer in that office since they are the same, and backup is made easier as we only need to have one base system image to recover to instead of having to have images of each computer system. Now, I know this means that a lot of the "individuality" from each computer such as user accounts might not be there in the base image, but no data is saved onto the individual computer systems, it's all done off the file server.
And that'd be my final point. If you've got multiple computers networking together continually sharing data back and forth, it's more efficient to offload that duty to a dedicated file server of some kind. With only a few computers in the network it doesn't have to be anything fancy. A NAS device or some of the pre-configured HP home file server systems are a great investment to store your data in a protected RAID configuration. Plus, your workstation computers aren't having to "double duty" dealing with sharing out and protecting your data as well as doing your design or RIP work. Once you start getting five or more workstations continually pulling artwork and customer files all day off the server then you may want to step up to something a little more powerful, but it still doesn't have to be tremendous, $1,000 goes a long ways!
The list of things that you can do to further streamline your business technology, improve your performance, and increase your data security just goes on forever. It's simply a matter of what you wish to budget to accomplish it, and who will do it. There have been many discussions on here throughout the past several years which detail many of these things quite well I think, which is why I am so glad to be a member here to help discuss these technologies, help others in developing their business systems, and learning something new myself.