For almost all web video, people seem to prefer YouTube and Vimeo as their hosting provider. I have enabled HTML5 video on both YouTube and Vimeo. Since I try to keep my browsing experience for the web contained within Safari with Flash removed (as if I had bought a new computer without Flash installed), I sometimes load Chrome for when Flash is absolutely necessary. (It's the John Gruber Way, slightly modified to use AppleScript to copy the current Safari tab into a new Chrome tab and FastScripts to assign a keyboard shortcut.)
Watching video on the web continues to frustrate. HTML5 for the most part eliminates the fan running (the original impetus for Gruber's decision) but there remain other annoyances:
The need for a plugin to change embed codes on websites to use the HTML5 player.
occasional white screen when maximizing an HD video
playing the video runs up against the buffer, which induces stress. This might partly be an issue with connection speed. I still have to play a video then pause so that it can buffer, wait a minute or two if the video is particularly long, and then hope that the playback doesn't catch up with the buffer.