After my worry about sound, it appears that downloading and compiling a sound app via emerge, sound was there all along (or was sorted by a dependency that was downloaded along with the sound app). I’m currently trying out a program called Rhythmbox which so far seems quite powerful, but rather crash prone. It will play quite happily, but if you do something weird, it will just die. However, it is in active development so I hope it will stablise once all the features are there.
I like Rhythmbox because it build up a library of your music and it has a nice clean UI that is simple to use. It is based on the same concepts as iTunes, so I would guess that many of the UI concepts came from there. I haven’t used iTunes so I can’t verify that. In the end, I think it will be a good app once it has matured.