High Quality Video for Web

A few weeks ago, a colleage of mine emailed me asking a few questions:

1. What export settings are best for iTunes podcast? High quality
2. What export settings are best for YouTube? High quality
3. If you are familiar with Vimeo, what settings for this? High quality.

And the following was my answer:

As far as the "best" quality settings for uploading to sites like YouTube, I don't have any technical rules - more just a rule of thumb that you want to throw more quality at it than it would stream at. For example, most sites stream at a max of 400 kbps, so I'll render my videos at 512 kbps and upload that. They transcode them for flash on their servers, and that becomes the final quality that people will stream. It doesn't matter what format really, but I generally use wmv and occasionally mov.