CPU Temps (Running hot!)

I have an Intel e8400, which constantly idles at around 44c for core 0 and 37c for core 1. This seems rather high, but I haven't the foggiest why. I recently bought a new case that accommodates cooling, the Xclio Wind Tunnel, and as well have an Arctic Freezer Pro 7 CPU fan. I've reseated the fan many times, replaced the thermal paste with Arctic Silver's guide, everything I can think of, but to no avail.

I have a thermal sensor which displays the temperature of my computer. I have it placed on the heatsink that is just below the CPU on my motherboard (ASUS P5N-D), saying 37c.

So, what am I doing wrong here? Plenty of air flow, plenty of space, an exhaust fan, two 25cm intake side fans, and a CPU Fan. I don't understand why the processor is reporting it so hot (Using Real Temp to find these temperatures btw)