Depends on if your games are threaded, I would recommend the 6000+ if you run at stock, the 8650 if you plan to OC, however the original Phenoms hit a block at 2.5/2.6GHz.
I would recommend the Athlon X2... I would only go higher than a dual core with AMD if you go with a AMD Phenom II or so. Those processors are overclocking phenoms... Meanwhile a X2 6000 can be overclocked to run faster than a X3 processor and is more overclockable... well in my opinion, of course it varies depending on your fan and heatsink and cooling solutions you apply on it