where it's at

adjective2

1. •
   (informal) cool, trendy

   • 5 March 2012, Daily Telegraph, Stockholm: on the trail of the Girl with the Dragon Tattoohttp://www.telegraph.co.uk/travel/cruises/9111563/Stockholm-on-the-trail-of-the-Girl-with-the-Dragon-Tattoo.html In fact, for armchair sleuths, Scandinavia — where waterfronts swiftly segue into gritty, albeit imagination-based, crime scenes — is where it's at.
2. •
   (informal) true, truthful

   • You say I let you down, you know it's not like that. If you're so hurt why then don't you show it? You say you lost your faith but that's not where it's at. You have no faith to lose and you know it. — 1965