HTML 5 is still in draft (Editor's Draft 5 June 2010), however if you are looking to create sites that implement some of the new proposed features then why not use some of these APIs today.
Examples of CSS 3
- iphone icons in CSS3
- CSS AT-AT
- Web Designer Wall CSS 3 examples
- 10 Amazing Examples of Innovative CSS3 Animation
Video/Audio API W3C Specification
What is html 5 video? (wikipedia quote...)
HTML5 video is an element introduced in the HTML5 draft specification for the purpose of playing videos or movies
Canvas W3C Specification
What is Canvas? (wikipedia quote...)
The ability to draw, render graphs, create graphics, or other visual images on the fly.
What is Storage? (wikipedia quote...)
Web storage can be viewed simplistically as an improvement on cookies, providing much greater storage capacity (5MB per domain in Mozilla Firefox, Google Chrome, and Opera, 10MB per storage area in Internet Explorer) and better programmatic interfaces. However, it differs from cookies in some key ways.
What is Geolocation? (wikipedia quote...)
Geolocation is the identification of the real-world geographic location of an object, such as a cell phone or an Internet-connected computer terminal. Geolocation may refer to the practice of assessing the location, or to the actual assessed location.