Motorik
Kick Henry Jackassowski
Oh that's a tough choice! I'd say after a burger or anything in the BBQ realm really, I'd go with vanilla. If it's Italian food, I'd pick the chocolate because it goes well with an espresso and then it's basically a hot weather variant of dolce e caffé, which requires a grappa, and that is not at all a bad thing.
Vanilla with limoncello!
Put two shots of rum in the chocolate shake and you have a tasty boozy treat.