Full load. For me it is useless to know what temps I am getting when I am not using my computer. The only time idle temps are good is when comparing them to full load temps to see if how your cooling system is performing.
I use speedfan, but motherboardmonitor is another good choice. ntune is ok for nforce systems also.
I load the system up with prime95 or CPUBurn and wait about 5 mins.