no matter what system is used for cooling larger heat sinks, water coolers etc nobody can know in what conditions the computer is going to operate under. and based on my own experience I would like to put forward an idea for your consideration.
a completely enclosed case with filtered and cooled air induction. the air cooling to be variable so as to maintain the temperature inside the case such that the heat generated by componants is able to dissipate into the air with maximum desired efficiency. a means of exhausting the air in such a way that the air replacement volume allows the differential between the air and componant temperature to be maintained.
The inside of the case would be a self contained environment dust free and much like a clean room, less dust is good.
I have had experience recently where a computer (not mine) had switched itself off and caused the operating system to have a hissy fit complaing it had not been shut down properly, but what can you expect if you operate a computer in a warm dusty room with a computer case that has more holes designed into it than a fishing net.
with the design I propose I hope that a computer would be able to operate in any environment at maximum efficiency. Remembering of course that operating in the Antarctic the air would not need the cooler to be activated.