HTML 5 is sure change the way we (web designers / developers) make sites, it has many new features tags, API's, that look pretty cool as said by the WHATWG team
XHTML made a good impact on the industry when it was released so i am quite sure that HTML 5 will also dominate the industry, i surely can't to use it i hope the browsers are able to support it sooner..
Who would be the first to support it?
i can only guess of 2 browsers that might do the job well .. Mozilla's Firefox and Microsoft's IE.. i don't why but i'm getting a feeling that Internet Explorer will be the first to support it (maybe with alot of bugs) but it will
