It seems people are forgetting a lot.
It's not "Flash VS HTML5 Video" it's "Flash Video vs HTML5 Video"...
There is a LOT more to flash than just playing videos.
The thing is that regardless of what most people say, HTML5(with js canvas, css, etc) is hardly convenient to code many things that flash does really well. Currently we only have a couple gizmos and proof of concept games/apps in js... There are thousands of well made apps that work really fine in flash doing all of that.
I personally think that while flash is certainly not ideal, it is serving a purpose that html5 can not fill easily.(And unlike what people think, the flash vm is actually quite fast and efficient)
Obviously for presentation stuff or video, I will agree flash should go away(and probably will).
(Exception set aside of really artistic & filled-with-transitions artistic websites, with little content, where it's fine)