I recently spoke with a cutler/blacksmith at a RenFaire. We got around to the nature of the edge on swords and knives. He was most emphatic that the last thing you want on any chopping or slashing tool is a highly sharpened is a supersharp edge as they are too vulnerable to dulling.

Taking this a little further, the same applies to a cleaver or chopper. The purpose of these tools is to be chopped into joints and other tough objects, such as the denser squash varieties. The angle of sharpening would be larger than for knives doing slicing as the primary job. My grandmother's chopping bowl, with ulu-type knife [known by our Italian neighbors as a mezzaluna] is still with me. It is not supeer sharp, as the movement is more of a vertical chop than a slicing movement. By the same token, don't let them actually get dull or chipped.