[quote="zopeka"]Thanks for all your reactions to my original question. In the end, based also on all your feedback, I decided against the Optiplex. The thought of paying a premium for a completely proprietary system that might *still* be too loud for my taste was too much to bear.
Instead, I picked the Asus Pundit SFF system, put together by a local shop/integrator. This is only partly proprietary, and I got much better bang for the buck. Ironically, I find this box still too loud, due to its 1700 rpm minimum fan speed, even at low temp. So now I'm shopping for (a) a suitable Asus Pundit mod or config adjustment and (b) maybe an Optiplex SD after all, because I need two new systems...
Drats! Anyway, thanks for all the help so far...
We have all three form factors of that model (GX260) side by side, along with a Dimension 450 and a couple Gateways. The Small Desktop and the Small Form Factor are quieter than the Small Mini Tower, mainly due to the size of the fan on the Small Mini Tower. Though, all three are near dead silent. We had to unplug an LCD projector which has a fan running all the time, just to hear them. They were noticeably quieter than the Gateway E-4000 small form factor cases.
I think you would be hard pressed to build a quieter system then a Dell, without going with drive isolators, fan less heat sinks, etc. Arguments about proprietary components and upgradeability aside.