I believe static electricity can damage the mobo, the cpu and memory chips. Can it damage the optical drives or hard drives? I wouldn't think that it could.
static could not really do much for the platters on a harddrive except to corrupt data. But all the drives, hd or optical have circuit board components, which could get fried by a pop from esd
I'm a bit paranoid about that. Last time I put together an old computer wearing that anti static strap, but couldn't get it to run. So I'm going to put it together in a garage with a concrete floor later. Probably I could get away with it on carpet but ... that's a lot of money on the line there.