For only 11 more, I would recommend the Athlon II 640. It is a quad core processor but without the L3 cache of the Phenom series. Now L3 does make a difference in gaming but games also take advantage of 3 cores on average. Plus, the quad core will be better for other tasks as well allowing for a little bit of "future proofing".
Thanks Jedi - the RAM change is a great piece of advice.
However, I am aware of the Athlon 640, but when it comes to cores, the Phenom can often be unlocked to a quad core. I believe this is quite common. What it can end up 'being' is a Phenom 1055 or something with a little overclocking.
I have read in loads of places that people have done this; both users and critics.
The Phenom only has 2 cores that can be unlocked making it at most an X4 965. However, there is no guarantee that the cores can be unlocked. Many people have been able to successfully do that and others haven't. I would buy the X2 knowing that you can live with 2 cores and additional ones are a bonus. I would hate to have you purchase it expecting to unlock them only to find that they are unstable. If you get one or both cores unlocked, that would be a great value. Again, no guarantee though.