on the O/C front i find this to be a very good program;
Asus Ai Booster
http://www.tasklist.org/task_OverClk_exe_6775.html
it gives you the CPU temp and fan RPM, but most importantly allows you to change the FSB in windows without restarting your comp. but if you don't have a CPU sensor then the temp will still not appear.
My CPU runs at 51 idle but it's a P4 and O/C plus my CPU cooler has a fan control and runs at 1500RPM when resting. also my 7800GT runs at about 50 idle but only goes to a max of about 65-70 and it's O/C about 15%.
Windows 7, Asus P5Q-E iP45 , Core 2 Duo E8400, 4GB Ballistix DDR2 800MHz, GeForce 9600.