I think video will remain one of the last applications of Flash on the web, because there is no way to implement DRM in HTML5. What's interesting is that even the latest video chat applications by Facebook and Google do not use Flash but their own proprietary plugins (though Google aims to replace this by standard web technologies).

What other use cases are there for Flash (let's say in one year, when HTML5 capable browsers will be the default for everyone and their grandma)?

You're trying to dilute Flash into a few "kinda necessary" features.

  * The kind of 3D coming from Flash Player 11 makes WebGL look bad.
  * Audio API?
  * How about recording via webcam (kinda important to YouTube).
  * Not sure how HTML5 stacks up against Flash in terms of handling advertising 
  (also important to YouTube), but I think Flash wins here.
  * Flex, Adobe AIR?

Oh yeah, technology also evolves.

As much as I love the concept of open web technologies, a revolving truth has become painfully clear: What you might be able to do in HTML5 tomorrow, you can do in Flash today.

I'd phrase it slightly different: What you will be able to do in HTML5 everywhere tomorrow, you can do in Flash today on desktops (assuming your browser does not crash and you can live with the roaring sound of your cpu fan).

Or even better: What you might be able to do (pending royalties, patents) tomorrow with HTML5, you can do with Flash today without worry of being pursued by a consortium representing a specific codec you may or may not be allowed to use.

The "my fan turns on when I use Flash" is weak. I use a MBA and I can tell you just about anything involving video or any sort of high resolution graphics gets "the fan spinning".

I love the "you can't play Flash video for more than 6 hours on mobile devices!" argument, too. You know what else I can't play for 6 hours? Angry Birds, Netflix, Sonic All Stars Racing or even TuneWiki (audio) or any of the other semi-demanding apps I use. So Flash is supposed to be better than all that?

DRM will be obsolete, because there's no consumer demand for it.

But there's consumer demand for content. By your logic, the web will be advertisement free in a few months.

There's tons of demand from consumers, if the consumers of your product happen to be movie studios.

end-consumers.

There's plenty of content-provider demand, though. :)

So what reasons are there to use flash over HTML5, I ask myself and the HN crowd?

  -Video. (Mwoah, only non-WebM video, can't really count this one)
  -Webcam
  (thanks garethsprice)
  -Simultaneous sounds (thanks AndyJPartridge)
  -Cross-browser support (browsers interpreting HTML5 differently) 
  -???

Non competitive advantages:

  -Games (see Angry Birds)
  -3D hardware acceleration (both have the same security issues exposing shaders)

Competitive advantages HTML5 over flash:

  -2D Hardware acceleration
  -Open
  -Cross-browser support (flash has it's update/versioning problems)

For me, the biggest problem I have trying to use HTML5/Javascript/CSS for a game is sound.

I can't get background music and sound effects working simultaneously under iOS using just those standards.

is that a deficiency of the iOS browser or the HTML5 standard?

iOS mainly: Sounds need to be triggered by touch events, which of course for gaming seriously restricts what you can do.

EG: No sound effect from an alien shooting at you.

There's a pretty massive software ecosystem surrounding Flash. Tons and tons of mature libraries for Flash. Not so much for HTML5 (though that will change with mass adoption and time).

Cross-browser support. Getting much better, but HTML5 is still a pain to test/debug cross-browser (or, "in IE and in everything else", which is mostly what CBT comes down to)