I suggest you follow the guidelines (the link's in my signature). We need to at least know how much you're looking to spend, what parts you need, and what parts you already have. Everything else in that link is good to know for putting togther a full build without need to ask too many questions.
The AMD vs. Intel decision is almost entirely price driven. Generally, if your budget for the entire tower is under $1,400, AMD is a better choice. If you're over that, Intel dominates. Even with that said, no one should recommend the X6 CPUs for gaming. They're out done by the cheaper X4 955 for gaming purposes. The real arguments are when it's better to go from the X3 440 (generally anything under $1,000) to the X4 955 ($1,000-$1,400) to the i5-750 ($1,400-1,600) to the i7-930 ($1,600 and up).
Your GPU should be fine. It's actually fairly powerful. The only thing that's "wrong" with it is that it doesn't support DirectX 11, which isn't very important for right now. I'd wait until games are actually using it to replace it.
The 955 is a good choice for the CPU. A better board would be the Gigabyte GA-790XTA-UD4. It's cheaper and more future proof as it has a second PCIe 2.0 16x slot that operates at a useful speed (the Evo's second slot only runs at 4x).