Let's clear up a few things about Flash.
1) Flash is a memory/CPU hog.
This is 100% true. Flash 9 on Mac OS X would essentially make a Mac unusable with just two Flash ads on a web page. Things have gotten better in Flash 10 and 10.1, but it is still very resource intensive for even basic operations.
Is there any reason Flash should consume vastly more CPU than software such as VLC?
2) Video on the web must be protected. Flash support is vital for DRM.
I hate to break it to you, but most websites are already moving in the dual Flash/HTML5 direction. DRM might be "necessary" to some content providers at the moment, but we'll see how long it lasts.
Do a reality check and tell me how much content protected by DRM isn't already available on bittorrent, rapidshare, et al. Even Blu-ray disks protected by advanced DRM like BD+ are ripped by software such as
http://www.makemkv.com/
3) HTML5 is just as resource intensive. There is no benefit.
This is a curious arguement. HTML5 video support has just been baked into Webkit based browsers within the last 3 - 6 months and is barely more than a beta while Flash has been here for over a decade. It seems like within that time Flash would have been made so efficient that HTML5 couldn't compete yet a technology that isn't even hardware accelerated in most software packages can match or beat Flash within 3 - 6 months of release.
HTML5 needs a high level IDE like Flash uses (come on Google, Apple, etc..?) so people can shut up about Flash. It is a CPU hog, it is a security risk, and it needs to be put out of our misery.