game-changer / ɡeɪm ˈtʃeɪndʒər /

If you want to create big expectactions about something or someone, say that it is a game-changer. Really. This is not only a cool, modern expression, but it is also applied to cool, modern stuff. So twice as cool.

Game-changers are supposed to be so different, that things will never be the same. Theoretically game-changers could turn situations worse, but I have always seen it used positively.

Example 1:

iPhone 4S Camera Hands-on Review (time 15:15)

From time to time, a new product comes along that completely changes the way we do things. Fifteen years ago that product was the compact digital camera, that changed the way we take everyday photos. Today, the iPhone 4S could be considered the game-changer

Example 2:

From the dialogue between a womanizer and his friend in the movie: Crazy, Stupid, Love

- I met a girl.

- Oh, really?

- She is a game-changer.

- A game-changer? No way.

- So much I want to meet her mother right now.

Example 3:

And if you want to learn who are today's game-changers according to Bloomberg, they have even created a documentary series (highly recommended, by the way):

http://www.bloomberg.com/tv/shows/game-changers/ 

The list contains the usual suspects (Steve Jobs, Mark Zuckerberg, Richard Branson, etc.) but also some surprises. You can watch it online, so check it out.