I do not think there is an important media player that is already in the latest SOHO, that is, mplayer.
On my current SOHO5.1.1, there is a mplayer plug-in that does not seem to work when I want to watch on-line video.
It would be nice to be able to automatically download a missing plug-in or codec and watch a video right after, like in Windows.
I think the Thunderbird email program is nice and you don't even have to install it, to get it to work. More software should be like that, if there are no disadvantages to the method. Of course, for the larger programs, it is probably not yet possible to just copy a directory and start the program in a finished state.
I do not have extensive experience with email programs so my choice for Thunderbird might be, not that objective.