Tairaa, the pirates don't seem to be any different than Somali 'warlords'. I seriously doubt they're improving the quality of life for all Somalis; odds are more in favor of the pirates improving their own quality of life at the expense of other Somalis and everyone else involved.
Boeing's Pegasus class hydrofoils were decommissioned in 1993. They carried 8 Harpoon missiles and one 76mm gun, a bit much for anti-piracy, though it'd be fun to watch a 50 foot fiberglass 'pirate boat' vaporize.
Lockheed-Martin's 'Sea Shadow' would look totally awesome and scare the sh*t out of the pirates, if it were active and armed, but it's neither.
There's the Mk.V, but it's not intended for ship-to-ship combat. Aluminum hulls do not qualify as armor.
About the best we have available--that our sailors might survive attacking from--are our frigates, which are large and relatively slow. Not that it matters, because helicopters and aircraft are far more effective than any surface vessel.
Of course, I don't care if the pirates survive or not, either, since they're a murderous lot. Arrr.