I think pipes might be a strong contender. Currently titanium is roughly the same price as copper, but harder to machine -- and it's produced in ugly forms by the Kroll process. Electrolysis produces a metal powder using less energy. Titanium is practically immune to chloride corrosion but is slowly worn down by fluoride, although fluoride is typically present at just 1 PPM in tap water (anything higher is toxic) so Ti pipes should last quite a while. Boats can also be made of titanium alloys. Anything dealing with water gets easier when titanium is in play, for the most part; one of the few things that really affects it is lactate (biofouling), but even that can be inhibited with the right alloying additives. More speculative uses might include offshore wind turbines and underwater (isobaric) compressed-air energy storage equipment.