I don't have a shelf, but I do keep one of my most important accesories on top of my external burner (which is on top of my HD, making a small shelf). That accesory is my pair of headphones. I can blast Hevein really loud and no one else finds out
Hopefully its not. Its got like 3x as much stuff on it now.
It would be a meltdown if it ever did fall down. It would shure crush my MBP and Dell Monitor.