Need some sort of cloning program, not sure which one

So I have multiple computers, and my main computer, my macbook pro, has all of my music on it. I'd like to back it up, but I don't think time machine is the right program. I'd like to sync my macbook pro music folder with my mac mini (faux TV) and my girlfriends ibook. I haven't found the right program that I need, so I'm asking for your help.

The reason I don't want to just stream it is because front row doesn't stream album art, and I commonly find myself wanting to listen to my music when my macbook pro is closed and I just don't want to deal with the hassle of plugging it in, and I hate having to figure out which albums I've added and copying just them and blah blah. But yeah, any help would be greatly appreciated.

 

the thing is, I don't want to copy the entire computer, just the macbook pro music folder to the mini and ibook, and that doesn't let me choose just folders.

edit. it's also $27.95 :|