I posted this URL in another thread, but it is a great view of the whole video format "war" going on.
Even with chrome supporting h.264, in order to get maximum compatibility for video playback across all browsers(let's not leave out Android and Iphone), you still need to have the video in all 3 formats(below is copy/pasted from the site). Chrome isn't going "backwards" compared to where it stands now, unless you prefer having site visitors standardize on a set of browsers, in which case I can't argue with that:
For maximum compatibility, here’s what your video workflow will look like:
1. Make one version that uses WebM (VP8 + Vorbis).
2. Make another version that uses H.264 baseline video and AAC “low complexity” audio in an MP4 container.
3. Make another version that uses Theora video and Vorbis audio in an Ogg container.
4. Link to all three video files from a single element, and fall back to a Flash-based video player.