I think we have a revolution about what we (developers) can do with HTML. That's great 'cause with that we have a bigger learning curve. And I think that's happening very quickly. ( and I can say the same thing about CSS3)
But what doesn't make me feel proud about HTML5?
Only the Internet Explorer 9 will suport HTML 5 and maybe some CSS3 properties (on the other hand Firefox that already support this some CSS3 properties ).
So we still have that old problem...you can learn, you can develop your source code and make magic with HTML 5 and JQuery, but it wont render everywhere (maybe you can use that black magic...).
On other hand, using Qt, you can write applications once and deploy them across many desktop and embedded operating systems without rewriting the source code. Rá!
(but I know...Qt won't save the world as well)