Mozilla Firefox 3.5 is the culmination of nearly a year-long quest to build a browser for the next version of the web. And while it’s not perfect, it comes very, very close.

Firefox 3.5 brings with it entirely new and much faster rendering engines for both static web pages and the JavaScript code that powers today’s complex web-based applications. There are new privacy features, new capabilities for playing video and audio files and improved search tools. There are also a handful of other new features that should prove useful for both Firefox devotees and newcomers alike.

The open-source browser is expected to be available for download Tuesday morning for Windows, Mac and Linux.

Originally envisioned as a quick follow-up to 2008’s release of Firefox 3.0, Mozilla ended up packing in quite a few extra features into its flagship browser and spent months making sure that Firefox 3.5 was the fastest, most powerful Firefox yet.