Um this HAS been suggested before, turned down because as Soccer said it is a GAMING website, and you can't just think about the members you have to think about the people that come to play the games and that aren't members.
Oh and simply projectplaylist, or youtube link is best as of now.
This would be kind of cool, but has always been rejected before because of several reasons :
1. As those above me have said, this is a gaming website, not myspace or facebook. If you want, open up a new tab/window and listen to a playlist. I doubt you would be on your profile long enough to listen to a whole song anyways.
2. Moderators would have to be constantly patrolling the site looking for explicit and inappropriate songs, and they have enough work already.
Firetail posted out EXACTLY what kevin said. And why would you want music of your own profile? Listening to some repeated junk on your profile and other people's random songs on their profile.