I’m just back from the Mozilla Summit 2010 and I’m pretty excited about the demos I’ve seen there about the future of Firefox and the open web.
HTML5/CSS3 is most likely the next big thing on the web and Firefox 4 will be there to support it.
There is a really cool demo I would like to share: (note the dynamic real time content from twitter and flickr and also that this animation is not a video)

And once Firefox 4 with WebGL support will be out we will hit again the problematic situation on Linux about X.org, OpenGL and graphics drivers. (And for this moment I still need to embed the above video as Flash object to not ignore the people using non-WebM enabled browsers ;-))