HTML 5 and Flash

It looks like i'm the first to answer this edgy question...

despite the troll and war thing...

i'd prefer to use Flash for heavy (yes you heard me...) apps with many sprites to load, for dynamic advertising websites, for hugely animated web apps, for photo and video "editing", for 3D, for games also (i mean real games...).

to make everybody happy let me say that for everything else you can (and should) use HTML5 because HTML5/CSS3 is for "lightwheight" web apps for nice lightly animated graphics and cool interactions, nice embedded videos and free formats!

I attended the HTML 5 workshop at Web 2.0 Expo (slides available) and I was very impressed with its capabilities. A couple of reasons that you may want or need to continue using Flash instead of HTML 5:

1. You're a designer and you're not interested in learning Javascript. (Tools like Dreamweaver may evolve so that you can develop HTML 5 websites without learning Javascript)

2. You need to support IE and you don't want your visitors to have to download a plugin like Chrome Frame. For example, people working in larger organizations or governments option aren't able to download plugins to their machines.

Both of these reasons will probably no longer be applicable as support for HTML 5 improves.

gogeric is absolutely right - Flash for the stronger hardware, more robust experience and advertising - HTML5 for the really useful stuff that can be accessed on just about any device / browser

I would use flash for building complex software applications that run either on the web or desktop(AIR). one that is component heavy...and most probably integrates backend technologies like java, .net or php or coldfusion.
Html5 i think is very great. but i would use that to build your typical web apps. Like most people have said...light apps. I wouldnt load 50,000 rows of data using html 5... i would use actionscripts amf binary format for that. I would also use flash for complex games... 3D perhaps.
i love both technologies. but its always good to know which one to lean against when that time comes. it shouldnt be war...its sad to see so much hatred going on about flash. hatred never solved anyones problems... solutions did. So its best to know which solutions are needed for which task!

best of luck to all
Kofi