When compiz is enabled, playing a video in totem (or music with visualizations turned on) leads to strange things. For example moving the video player leaves the actual video behind until the player is dropped. Also, making totem transparent, leads the video to become black. An interesting thing I have found is that if nautilus (the part that makes the gnome desktop have icons) is disabled I find that moving totem leaves the video playing the same place, so it's almost as if when compiz is enabled and the user tries to manipulate the player, the video gets drawn being everything else.
I have tested this on other distros and for the most part they all have issues with it. The exception is Fedora which seems to have this issue ironed out, perhaps they have a working patch.
I have a Dell Inspiron 649m with intel 945gma video card. I am not sure if the issue lies with the intel video driver alone or if it involves both the driver and compiz. The problem isn't serious but it is obnoxious. I think it would be great if this was fixed in time for hardy. (NOTE: As of Hardy Alpha 2 the problem persists)
Please, if there is anything else you need to know about this or if there is anything you need me to do/test feel free to ask.
Edit: I also wanted to point out that this issue is not only with totem, but with other players as well.