ATI is believed to come with 5000-series cards which won't, according to the rumour mill, be a revolutionary advance performance-wise (but a significant advance nonethless), but price/performance wise instead. ATi is pushing GDDR5 for mainstream, which allow for narrower memory buses (=smaller and cheaper die without sacrificing performance), and the 40nm process is apparently making the GPUs even cheaper to manufacture.
NVIDIA is working on its GTX300-series lineup, but I don't know a lot about them...