although it's probably twice the size, mplayer (of all things!) that is, curaga's nodeps version, is twice the size of moc but also plays flv files.
i wanted moc because i just wanted a simple thing i could feed a list of mp3 and ogg files too with &exit to close the term and let it play (or run it from vt.) when there's no video, mplayer actually suits my purposes quite nicely, and if you run it from vt, it will even play the sound from videos without opening a window
i used it in tc yesterday and i've replaced moc with it in xubuntu. that means i shouldn't need to use vlcplayer either. (thanks curaga)
for putting music together, i've always wanted something like lmms, i thought the closest thing linux had was hydrogen (it's just drums.) it's massive and complicated, but someday it would be very cool to use.