After a little background reading, plus comments here, I've dropped the
Peltier idea - there is much more to it than just plugging one in and
designing a careful airflow round the heatsink, so I'll not bother with
that!
I didn't originally state the following as I was hoping for a simply
comparison table website with performance and noise figures that I could
read through myself, but I'm after silence, rather than overclocking and
cold. Environment in the room is 'normal' office temperatures 19-22 degC
(Scotland). I can easily research and find the maximum temperature of a Core
2 e6400, but what would you all say is a 'good' working temperature for
prolonged life?