Thanks to both of you for the info! I'll definitely start working through the mining subforum.
I'm reasonably experienced with Ubuntu, so I was thinking that it or another flavor of Linux would be best from a stability and possibly power consumption standpoint, but I wasn't sure how the drivers and utilities compared with Windows. I was hoping to run the OS off of a USB stick, to avoid running an HDD or CD drive and save on power, so I think that might limit me to Linux also (or can Windows 8 do that now?).
Also, is the general advice that it's best to use an open/no case with a box fan or similar, or to use a well-ventilated but closed case?
Thanks!
Well if you know your ways around in linux (console/terminal, not the Windows mimicing mode that Ubuntu is ;-)) that is a good place to optimize things as, like you said, you can reduce power consumption by only running the daemons you need and thus have the CPU run at low clock.
Windows from USB? I think it was doable with XP. I think the newer ones are not or at least it will be a lot more complicated than running linux from USB.
As far as the case goes: That depends on the room. If it is clean and cleaned of dust regularly you should be able to run in an open case, which of course beats a closed case temperature wise, if you're not using watercooling. Generally I wouldn't suggest running without a case or an open case. Dust in the wrong places can kill hardware just as water does. It's too risky in my view. I'd go with a case that has good 120mm coolers at places that provide a good airflow in the case.