If you're using any of the previous betas or Release Candidates of Mozilla's Firefox 3.5 browser, which is a major upgrade to previous versions, there is now a third version of the Release Candidate out. Firefox 3.5, RC3, is available for download for Windows, the Mac and Linux, here. Mozilla has a post up about the release here, although there aren't a lot of clear details on what is new in this release. The updates are very likely to be bug fixes and security updates.
Mozilla's post says that the updates in Release Candidate 3 are in response to "user feedback," but the company had intended to move quickly toward a final release of Firefox Version 3.5.
I've been steadily using both the betas and the Release Candidates of Firefox 3.5, and it's very speedy, stable, and has more than 5,000 features not found in other official releases. If you're already running a Firefox 3.5 beta or Release Candidate version, you can obtain an update to RC3 by selecting "Check for Updates" from Firefox's "Help" menu. There are Release Notes here.