Your poll is closed.
Anyway, nVidia has more market share, but I'd say they'll be losing some to ATi, until they can get back onto their feet with something better than the GTX 480/470, although I must admit the GTX 470 is very well priced. ATi is pretty popular right now, because they have well-priced cards aimed at all different markets - the HD 5970 at ~ $700 USD for flagship performance, the HD 5870/5850 for ~ $400 & $300 respectively more high end performance, then you got the HD 5700 series for less than $200 for decent, mainstream performance. After that you start getting budget gamer cards like the HD 5670, and HTPC cards such as the HD 5500 and HD 5400 series.