I think I have too many computers (eight) to make them all quiet so I keep them all in another room. It is really easy and not at all a PITA. What do you really need aside from a bunch of extension cords?
The monitor is the hardest part, whether you're using VGA or DVI or whatever you need to get the highest quality extension cord you can. I mean seriously pay as much as you can pay, up to $100 for just the extension cord. It makes a huge difference in quality and the cheap ones are completely useless.
For the keyboard/mouse I use a standard USB extension cord and connect them directly to the computer (no hub) because I heard that was best. I've never had a problem with them.
For everything else I just run one standard USB extension cord into a USB hub in my main room and connect everything else to that... printer, trackball, mixers, dvd burner, backup drives, footswitches, etc.
Almost forgot, also a couple MIDI interfaces that I connect directly to the computer via extension cord. Fortunately it has enough USB ports. I could have left these in the other room with the computers and run MIDI cables to them but it was easy enough to use extension cords and I've never had an issue with them.
For the other computers (I don't know if you have more than one), I use remote desktop over ethernet. It works so nice, control everything from your main screen. However, I also did run all the cables to have a separate monitor and KVM switchbox in my main room because sometimes you just can't rely on software. This was much more of a PITA, especially with that many computers. However, I rarely use it and if I was going to do it all over again I would have set up the KVM switchbox and monitor in the other room with all the computers. I could go in there to use it when I need to but otherwise remote desktop is the answer. Hope that helps.