I like myspace for the music.
I like livejournal for the indepth-conversational posts.
And I like facebook for the spontinatity.
Livejournal is my intellectual, Myspace is my musician/artist, and Facebook is the friend who knows all my friends and I see at all the group gatherings.
Livejournal I've known the longest, but to which has never evolved into more. Myspace is the place I go for new sounds, new ideas, a great idea, but I don't chat or message there. Facebook is the place I can feel surrounded by friends, even if I do nothing, and I can say little or much and, well, it feels like a "party" in it's social options from little to a lot of participation, but it's super-active, not quiet downtime.
I can't give up any, and yet I don't have time to spend on websites: I crave real life. Thus I think facebook will win, since it's where "my friends are". Myspace will be my go-to for music investigations, listening to new local bands, but "just a friend" and livejournal is good when I want to ramble on like a long conversation. It's easier to have the conversation & music on a "as wanted" basis. Facebook is, with it's built-in automatic IM, the place to go when I want to connect to the group of friends.
Yeah, I think overall though, I just need to spend less time on the internet.