All the CSS Filters are gone in IE9 Platform Preview 3. the dom.filters property is undefined and even gives exception when it is read.
I really hope the IE team will make CSS3 2D Transforms in the next Preview! As without filters now we don't have anything to rotate, zoom etc. Those are well standard now: http://www.w3.org/TR/css3-2d-transforms/
It will be even more great if CSS 3D Transforms make it as well http://www.w3.org/TR/css3-3d-transforms/
Then IE will be finally leading again. leaving Safari and Chrome well behind