I am a great fan of Langoustine.
When they are just right there is something about the freshness and sweetness that makes them delicious.
It can be hard to find fresh ones, usually they are available either frozen or defrosted. In terms of taste, fresh is always best.
I like mine simple with a bit of mayonaise or aioli, but they are also nice split and grilled with herbs and olive oil as in the above picture.