[cninja]

Not trying to detract from IE9 here, but Opera already has a similar ability:

http://my.opera.com/core/blog/2009/02/04/vega

The interesting parts of the article are the implementation details about the sandbox.

[modeless]

Opera's hardware acceleration is vaporware. It has not been included in any release of Opera, despite that article being over a year old now.

[wagh]

It's not vaporware. It's been in Opera since 10.5. It isn't being used at all but it's still in the release.

[walkon]

The thing about Opera is, it only has around 2.5% of the market. IE9 will probably have over 30% of the browser market within two years, which is a major factor when thinking about any web development, especially with HTML5 features like canvas.