Just in case somebody missed it, Youtube supports now officially (?) HD. Unlike Vimeo et co., the HD clips are ISO Media compliant MPEG-4 files.

Too bad there's no way to search for HD content. Here's one.

link to them by adding &fmt=22 at the end of the link.

I think those who are not annoyied by Adobe's extremely poor support of MP4 will be able to click the Watch in HD link themselves.

Here's another to my eyes Vimeo still looks better but Youtube loads faster.