It seems like the release of Mozilla Firefox 3.1 Beta 3 is closing in. The Mozilla Quality Assurance team is organizing a test round "for the rollout of" the beta release today, and states that to test it, the 3.1 users just need to klick "Check for Updates" in the Help menu. I have tried it, but the update doesn't seem to be out yet. I guess it will arrive later today.
Some of the new stuff in Firefox 3.5 except TraceMonkey and great speed improvements are "Private browsing mode", support for embedded video and audio (without Flash etc), improved rendering (improvements to the Gecko layout engine, including speculative parsing for faster content rendering) and of course lots of bug fixes.