Currently, the Samsung Galaxy S7 edge and S7 Active are probably one of the very best when it comes to battery life.
The Google Nexus 6P also manages pretty good runtime, provided the processor isn't under load, and if you don't live in the US, the Huawei Mate 8 has a pretty legit battery, if you don't mind Huawei's.....interesting choices with their EMUI skin.
The Galaxy Note7 is right around the corner along with the Nexus Sailfish and Marlin, which are set to bring in large batteries as well, so I'd definitely wait for those before making a decision.
