68-74F? Man, you like it cool!
From all my lifetime of experience in computers, I'd say the lower the humidity the better, but for one thing: Static discharge bites harder and more often the lower you have the humidity. The computer rooms I've worked in have generally been very dry, but have also taken static discharge into account with conductive flooring, etc.
Being in Florida, I almost never have a problem with static, because the humidity is just so high all the time. So the answer here is simple: As low as possible!
-Noel
Linear Mode
