I feel this may help you decide.
Thats a recent opteron that you may recieve if you order one.
An X2 4800 is 2.4ghz stock. an FX-60 is 2.6 stock. With appropriate cooling you can hit upto 2.8 easy. an opteron 165 will get you to 4800 stock speeds flawlessly. Its just a decision between Overclocking and Not overclocking. You may not know how to now, but you will want to know later on. an Opteron is my recommendation although recommendations differ. I predict with a recent stepping and better cooling like a big Typhoon, you can hit 2.8+ with opteron 165.