I'd go box section unless you have a pile of spare angle lying around as the end result tends to be stronger, plus clearing crud out of the shelf corners is a pain. Depending on the depth, put the under shelves on runners so that you can slide them out rather than having to rummage around underneath. Another good idea I have seen is to have a lidded hole in the top with a bin underneath, when cleaning the bench just lift the lid and sweep the crud into the bin. As for sockets - as others have said - put plenty in! If you can get them under the front edge of the bench top they'll be easy to get at.