The final release of Firefox 4.0 is drawing closer and closer. Earlier today, Mozilla outed its fifth beta version of the browser, which enables Direct2D acceleration by default and includes a handful of other, miscellaneous changes. You can grab the new beta through this page.
Direct2D acceleration was already present in the fourth beta, but enabling it required digging through the about:config page and flipping obscure settings. This time, according to the release notes, the browser offers hardware acceleration right out of the box for everyone running Windows 7.
Other changes include a new "Firefox" menu with more options, support for a new audio application programming interface, and support for the HSTS security protocol. More details are available on the Mozilla blog. (Thanks to TR reader SH SOTN for the tip.)