I don't see how they're going to hardware accelerate canvas much, unless you stick to very specific operations, i.e. never touch individual pixels. GPUs are great at splatting polygons all over the place; running arbitrary JavaScript to generate pixel values, not so much. Reading back pixel values from the rendering surface is pretty much out of the question altogether.

Unless you meant the fact that WebGL seems to be taking shape, or the hardware accelerated CSS3 effects. (I doubt HTML/CSS rendering is hogging the CPU here)