SNIP:

Something Leach does not say is that because there is no mouth in front of the
blade, your stock selection must be impeccable.  Just imagine trying to find a
10 foot or more piece of wood with straight grain the full length in a modern
lumber yard.

END SNIP

Well, yes and no.  

The Chris Schwartz method of getting straight grain lumber for workbenches works
pretty well, although a bit spendy.  The idea is to buy wide lumber -- say
nominal 12".  Generally, this will be from better cuts anyway, and will have
bands of straight grain in one or both edges.  Rip those sections and Bob is
close relative.

I myself do something like this with my oak and walnut.  I have walnut and  both
white and black oak in excess of my lifetime needs.  Generally, I have it sawn
through-and-through (right down the log the long way).  This yields stacks of
book-matched wide boards  that will contain varying degrees of flatsawn,
riftsawn and q-sawn wood.  If I want straight grain, I look for nice rift or
q-sawn stretches and rip them out.  Just did this with some rift-sawn sections
of walnut I want to use for table legs.

Joe