Actually, there's ANOTHER way to prevent balooning... Splitting vertexes. In Max, for example, select the faces for, in the example above, the front "ring" of the barrel (or whatever tube that is). Detach them as a separate object, then reattach them. You end up with the vertexes duplicated, but the surfaces don't share them - the outer and inner walls each refer to a different set of vertices, as does the thin "facing surface" on the front. The end result is that you get to keep your hard edge, use smoothing, AND not add a buttload of polygons. FWIW, whenever Rhino creates a mesh, it automatically adds vertexes to the surface edges, keeping those edges sharp.

Remember, kids! Napalm is Nature's Toothpaste!