A good 12 inch carving knife should be about one and one half inches wide at the butt end, and taper to a not too abrupt point. On the other hand a boning knife should be about 6 inches long and no more than one half inch wide at the butt end, it must taper to a fine point. With these two knives, there is little need for others. The taper of the blade is important. This refers to how the blade tapers from the thickest part to the cutting edge.
Most cheap knives are flat with the cutting edge double angled to a thin cutting edge.
The problem with this is that once the knife becomes dull, it is almost impossible to sharpen as one has to wear away the steel from the entire surface of the knife before the cutting edge meets the stone. A well-forged blade tapers from the top of the blade to the cutting edge. The intended used dictates which form is best. For most pocket knives and kitchen knives, a gradual taper is best all round. This is also the shape ideally chosen for the straight razors of old.