Asus isn't the only company to recently jump on the ATi bandwagon. Transcend and Soyo are also announcing their intentions of making ATi-based vidcards.
Transcend intends on having a high-end and budget line. The high-end will consist of the ATi chips (7500, 8500, etc) while the budget cards will be SiS315 based.
Soyo's approach will be different, as they're only doing ATi vidcards. They're playing with the idea of selling mobo and vidcard bundles.