I use Twisted Pixel. I think it's the closest to Milk Drop right now. It doesn't do the name of the song playing fly-ins and stuff like that but it does look pretty nice most of the time. There are a couple of others but Twisted is my fav. right now. Here is a list of other ones you might want to check out.
EDIT: Just looked at G-Force for the first time. Looks nice. May be my new Vis for Media Center Edition.