Either Man of Steel or Batman V Superman.
They work so well together that I feel they need to be combined as one movie. It's like you don't watch just one Lord of the Rings movie. Feel you need to watch both those movies as one. Hoping Justice League completes it as a trilogy as the writers have said it would.
Second place goes to Captain America Winter Soldier. Too bad Civil War was a mess, otherwise it could have been a great 1, 2 punch like Man of Steel BvS was. Cause their stories are also very connected as one.
As for a simple watch while flipping channels, I woudl say seeing either GoG or Deadpool on tv would make me stay and watch. Though sadly Deadpool is a double negative. It's not a movie I want to pop in a Blu Ray for to watch, but on tv it woudl be censored probably to unwatchable.
But Man of Steel, BvS, and Winter Soldier are movies that if I was flipping chanels and saw it on, I would watch probably about 10 minutes, then get up and go and grab my blu ray and put it in. The rest of the Marvel, DC universe I would not bother and just casually have teh movie on the background while surfing web probably. As said above the winners for background titles would be Deadpool and GoG.
