Fastest Way to Create a Replica

So.... I want to create another slave and I want to do it as fast as
possible. Normally I take a slave offline, record the position, do a dump,
import the dump, set the position and start the new slave.

....this takes forever...

I recently tried just copying all of the files over, setting the position,
and starting it up. This didn't work. Why? Or more to the point, what's
the fastest way to create a slave in MySQL?


Michael