if you are bored with your cpu i would do it. it would be fun to oc anyways.
i know the 631's are the killer overclockers, the wr is just over 8ghz. 0_o
if you ever wanted a dual core again, it would be an excuse to upgrade to c2d, or whatever is out then, or you could buy a 945 or something on the cheap.
it does depend on what you do with your rig tho...