If you jammed a bunch of waterproof shells into a big pot and boiled them down into a concentrated essence, it would probably look something like Black Diamond's Mono Point Men's Shell Jacket.  It offers fully breathable weather protection, courtesy of an ultralight Gore-Tex Paclite 2L membrane, but it packs down tiny so you never have to argue with yourself about whether those clouds look worse than they are. The Mono Point also weighs under nine ounces, making it Black Diamond's lightest fully waterproof and breathable shell. In keeping with its light-is-right design, it's not overflowing with features but has a harness-compatible chest pocket, helmet-compatible hood, and adjustable hem and cuff tabs that keep wind, spindrift, and drafts from sapping your heat and your strength.