This video isn't a bad introduction, but it is from 2009 which is long time ago in the history of HTML5. A few points:
1. SVG is extremely cool but very few people are using it. The video spends time on it but SVG is still lagging behind for various historical and political reasons.
2. Canvas has become the default graphics even though it has interesting problems.
3. Audio and video are a mess in some respects and Ashley has written about this eloquently, at least the audio part. I think we'll be stuck with H.264 video with open source trailing behind.
4. App Cache isn't catching on very much, and sometimes I think that is a good thing. If everyone started to use it, you'd see a lot of computers running out of room. <img src="smileys/smiley17.gif" border="0" align="middle">
5. Databases in HTML5 are very wobbly. There are several competing formats that sound cool but haven't gotten far. "localStorage" seems to work, sort of like big cookies. Web Storage I've been meaning to ask: what does C2 use for offline storage?
6. Web Workers is very cool but is just getting some attention.
7. They didn't mention Web Sockets which is starting to catch on.
I don't know that I can recommend any particular video or web site for an unbiased overall coverage of HTML5. But at the same time, HTML5 is really starting to do fabulous things and certain things seem to be here to stay:
B. Audio if you follow Ashley's rules.
C. Video maybe.
Firefox has a fabulous demo of HTML5 called BrowserQuest. It uses Web Sockets, Web Workers, Canvas, localStorage, and HTML5 audio. And some CSS3, which isn't technically HTML5, but seems joined to HTML5 at the hip.
As you probably can guess, I spend too much time every week reading and coding HTML5.