Since they bought ATI, AMD found themselves in the curious position of battling both Intel and Nvidia for market dominance. A very difficult task to accomplish, since they were losing badly on both fronts.
The troubled company seems to be getting somewhat of a leg up on the GPU side with the Radeon HD 3000 series (RV670) GPUs. Yield rates on these chips have risen to the point where cost of manufacturing has gone down significantly. And now they are planning to offer newer RV670-based cards, like the upcoming Radeon HD 3830, at lower price points.
Considering that GPU prices are still high for performance cards, it wouldn't take much for them to get a price point advantage against Nvidia.