Windows/Mac/Linux: If you ever have to rip DVDs to your desktop or convert video, you know how awesome open-source encoder HandBrake is. Well, it's just been updated with over 1,000 changes since the last release, including 64-bit support.
The 64-bit support is probably the most notable change in this build, as it allows you to encode videos about 10% faster than the 32-bit builds—in a lot of cases, bringing encoding up to real-time or faster. And, note that Mac users don't need Snow Leopard to see this improvement, long as they have a 64-bit capable machine (Intel Core 2 Duo or later). Linux users will also be able to reap the benefits of the 64-bit build; unfortunately at this point there doesn't appear to be a 64-bit version for Windows users.
Other changes include soft subtitles (it rips subtitles that you can turn on or off), a live preview mode (so you don't waste your time encoding only to find you had a setting wrong), constant quality encoding (for better quality video and no need for 2-pass encoding), and some cleaning up of the settings. It looks like there are no more presets for PSP, PS3, or Xbox 360, just one "Normal" setting that, in theory, will work with anything that supports Main Profile H.264. Also, AVI, OGG/OGM and XviD encoding have been removed from the program—the HandBrake team has apparently decided to focus on H.264 encoding and get rid of old codecs.
HandBrake is a free, open source download.