For most games, I prefer the formula, "Players use X to do Y," because the capabilities of the characters are usually closely related to their goals.
In Unknown Armies, players try to harness bizarre supernatural powers to to achieve insanely ambitious goals.
In Eclipse Phase, players use the strange technology of transhuman space society to defeat horrifying existential threats.
In Call of Cthulhu, players try to overcome their realistic human frailty to resist horrifyingly powerful supernatural threats.
In Vampire: the Masquerade, players use monstrous superpowers to perform elaborate clandestine social schemes.
In Base Raiders, players use do-it-yourself superpowers to extract wealth and more superpowers from abandoned superhero bases.