IMHO, they are both a waste of money....the real question should be getting either a x2 4400 or opty 170 or 165. This is because you can oc them to higher speeds than both of those processors and save about 200 dollars. If you don't oc then i dont see the point in getting an opteron unless you have some really high end system that you will be doing rendering work.
edit: get opteron if you oc, but if you don't oc, get the x2. You can even clock these past the fx-60
Proud owner of the only hampster powered rig on these boards.