Firefox developers have started applying the same rendering techniques for 3.7 (experimental builds are available), simply by adding a Direct2D Cairo backend (thus, all Cairo-based browsers may use it sooner or later), and they are now debugging it (it's functionally complete).
Firefox 3.7 (Minefield) already gets 96/100 on Acid3 (with html5 and SMIL activated), and has no more graphical glitches (some other browsers get higher scores, but don't match the reference rendering yet). This won't be backported to 3.6, which is already too advanced for such a patch.
Other platforms won't see the technology, because it's MS-only (but they have other equivalent technologies available).
A project to 'bottle' Firefox tabs has started too; for now, it's only the equivalent of spawning several Firefox processes in a single UI, but the goal is to dissociate the rendering threads, network stacks and UI process from each others.
What I'd really enjoy from IE 9: DOM 2 and SVG support.