Interesting topic. I echo the sentiment of most posters here that while HTML 5 makes great leaps in basic multimedia presentation, it won't be able to replace Flash. All the online gaming sites are a good example. Flash is can run on most browsers except on certain mobile devices.
On that note, I believe battery drain was the original reason why Steve Jobs did not want to support Flash on the iPhone and iPad. This might bite Apple (no pun) down the road. Android 2.2 will have flash support (but it not clear if all the hardware manufactures will support it -they'll have be confident in their batteries).
Also, it looks like Flash 10+ will be a sure thing on Blackberry devices going forward including BB phones the upcoming BB Playbook tablet (btw, this toy has some killer specs - can't wait to get my hands on it when it comes out next year).
I am willing to bet that Flash will continue to be big in Web Dev even after HTML 5 support becomes universal.
