From what I can see, aAt the moment if the screen-saver is active while Media Player is playing audio then the Play-Pause button does nothing. One has to first press the Menu button, and following this the Play/Pause button. I find this extremely inconvenient if (for instance) a telephone call came in and I want to quickly pause the audio. It would be much better if the Play/Pause button was active regardless of whether the Screen Saver is active. It is not a concern when playing video as in such a case the screen saver would not be active. However it is frequently active if one is playing music or an audiobook.
To further devevlop this idea, I would prefer it if the Play/Pause button stayed active even if I am navigating around the ATV2 menus. In other words the Play/Pause should stay active any time Media Player is playing audio in the background. In these cases the Menu, OK and cursor navigation keys would no longer be used by the Media Player However I realise this might be harder to deliver.