I'm building a wall length of hanging bookshelves and want to know what
anyone out there would build them with.

The shelves will be adjustable and go to the ceiling so I can continue
my crown molding around them. They will stop short of a desk area and
have recessed lighting to illuminate the workspace.

I plan to use 3/4 inch stock for the casing and shelves and 1/2 for
backing so I can anchor them to the wall. I want to know what kind of
plywood I should use. In doing research I've found that alot of people
use birch plywood. I'm wanting to know if anyone has ever used sanded
pine plywood before? I'm planning on painting the shelves so I'm not
greatly concerned about seeing the wood grain. I just want a nice
surface.

Any and all feedback is welcome.