My box stays open 90% of the time too, but then I have to clean the dust out 4x as often :/ -- Thinking of building a DIY 19" rack mount with water cooling to keep the noise down.
Sapphire Trixx also has a nice fan control even if you dont use the OC features.
If XP doesn't work out for you have a look at BAMT
https://bitcointalk.org/index.php?topic=28967.0 .. I haven't tried it personally, but it looks promising