That's fabulous. My WD2500KS idles at 31C, and gets up to about 35C during active periods, with a 92mm Panaflo at 7V blowing on it. I would not be at all concerned about your drive until it gets above 40C, and immediate corrective action is needed if you temperatures over 50C.
I am using SpeedFan. My Raptor is mounted in the drive cage on the bottom of my case, where two 80mm intake fans blow in on it. Look up some pictures of the case in my sig if you're not sure what I mean.
Anyway, here is a shot of my SpeedFan. Later on I may take a shot of it while defragmenting.
By the way, Temp2 is my CPU temperature as far as I know, and Temp3 is my case temperature. What would Temp1 be? Don't mean to hijack my own thread.