There has also been some discussion about the photo/video app, since it doesn't always find new movies you've copied onto the Touchpad.
One thing to watch out for is whether the directory is created as "hidden" (in Windows, right-click on the dir/file and go to "properties"). I suspect this has something to do with how permissions are set in the native file system; if so, it will be easy for HP or patch-creators to fix.
Even when unhidden, the app doesn't always notice that you've added video files/folders. A workaround for this is to install the most excellent app Internalz (see elsewhere on this site for how to find and install). If you use Internalz to navigate to your video file, you can then tap/hold to get the per-file menu and select "open". The video will then open and play.
I've still had difficulty determining when/how the forward and back swipes work; so far, it appears that they do NOT work in the open-with-Internalz method above.