fire rated drywall?

[Mark Andy <mark@sccaprepared.com>]

Howdy,

I'm going to be putting up drywall in my attached garage that will double 
as a shop for a year or two...

I figured I should use fire rated sheetrock.  What thicknesses does it 
come in?  I seem to recall back when I did rough carpentry as a student 
that we used 3/8" or maybe 1/2" sheetrock on ceilings, with 5/8" on walls?

Anyone know what's standard here?  I'm also wiring, so I need to know how 
thick the walls will be so that I can set the boxes appropriately...

Thanks!

Mark