Metal, aluminum, or wood for a rack ?

I built my rack with Pennsylvania slate shelves. If I could go back in time six or seven years I would get thicker all thread. That being said, I can stand on my rack also with no wobble. As for vibration, rap your knuckle on a 1 1/2 inch thick piece of slate and you get nothing but pain.
I loved the look of the slate when I built it but would probably like something a bit more refined now.

Elizabeth.
You're freaking me out man.

I have been researching looking for good audio racks, and i came across this:
http://www.audiav.com/

They have nice racks, worth a look.