HTML 5 is going to change a lot more than video too.
I like the dialog element.
It will allow you to post conversations like this.
Code:
<dialog>
<dt> Costello
<dd> Look, you gotta first baseman?
<dt> Abbott
<dd> Certainly.
<dt> Costello
<dd> Who's playing first?
<dt> Abbott
<dd> That's right.
<dt> Costello
<dd> When you pay off the first baseman every month, who gets the money?
<dt> Abbott
<dd> Every dollar of it.
</dialog>
Kind of silly, but I can imagine a couple uses for it. and there are dozens more new ways to play with HTML.
HTML 5 is still being authored but there's no reason it will not be adopted. Firefox is already supporting it and of course IE will lag, but there will be hacks. It degrades nicely anyway.
It's also going to help a lot with accessibility and the mobile market. At least it will help developers.