Coretemp, HWmonitor, and RealTemp are all good choices for monitoring CPU temperatures.
Everest, in my own experience, doesn't always label things in a very clear manner.
However, the other three programs locate the CPU temperature flawlessly in my experience. Although some programs can be more accurate than others (RealTemp is fantastic), any of them should work for you.
And having a CPU in the 40's (Celsius) is fairly normal for an 'idle' temperature with stock cooling systems.