The iPad plays DerbyVideos really well, the quality is astounding, but there are a few gotchas.....
The Apple iPad Safari Browser does not support Flash so you won't see the Flash based embedded videos on Layer9.ca - just big white spaces.
But Vimeo does support HTML5 which the iPad also supports so clicking on the Period 1 / Period 2 links for each bout will work, providing outstanding HD 720p video. For best results play in full screen mode on a high bandwidth broadband link.
Example Period 1
HD 1080p support
As of April 2010 Vimeo HTML5 support appears limited to 720P and 1080p videos don't play. Since vimeo 1080p requires a massively powerful PC and 99% of Vimeo videos are 720p this should not be a big issue yet.
Videos older than June 2009
Due to the way Vimeo stores their video, any videos older than June 2009 currently don't play on iPads, you can still download the smaller 640x360 versions at Layer9.ca ( see below ) which will play.
What to do about low bandwidth links
Vimeo videos playing in full screen mode on an iPad are outstanding, playing at HD 1280x720 so long as it's over a high bandwidth multimegabit Internet access, if you are limited to 1 Mbps or less then download the smaller 640x360 versions of the videos to your PC and load them into iTunes to transfer to iPad. They won't look as good as the HD format video but it will play.
Problems with Vimeo ? Down load these mp4 files which play on AppleTV, iPhone, iPod Touch, iPad and in fullscreen on PCs with iTunes or Quicktime. Mouse over the links below, right mouse click & select “Save Target as” to download. Period 1 (H.264 640x360 30 fps)
The iPad does support YouTube - Here's a link to the Layer9 Videos not all of which are on DerbyVideos Layer9.ca
Google Video Support
The iPad will be able to play old Google videos from 2007 & 2008 but the quality is really poor. If you really want to watch on an iPad click on the option to download the video instead - this will open a new browser window and after a few moments this will start to play the video from the download site - typical resolution will be 640x360, some from 2008 are higher resolution, quality is still fairly poor ,but this is more a reflection of the camera which suffered from auto focus challenges, the compression scheme and the ejit holding the camera.