Opera on Acid
Congratulations to the core developers, QA, and everyone else who's been working hard on this.
No publicly available build passes yet (so for now you'll just have to take our word for it), and there are still some layout issues to correct*, but Opera plans to a release technical preview version of a working build on labs.opera.com within the next week or so.
Webkit is close behind on 99/100 currently; they may well succeed in releasing a passing public build very shortly too.
* Remember that 100/100 does not mean that the browser passes the test fully, the other two requirements are that the animation has to be smooth and the final page has to look exactly, pixel for pixel, like the reference rendering.