Currently a friend and I are arguing about what the sides of the force are called. What I want to know is if the opposite of the dark side is called the light side or the good side.
It's called the "Light Side"
Han Solo calls it the Light Side of the Force in The Force Awakens:
REY: The Jedi were real.
HAN: I used to wonder about that myself. I thought it was a bunch of mumbo jumbo. A magical power holding together good and evil, the dark side and light. The crazy thing is it's true. The Force. The Jedi. All of it. It's all true.
Kylo Ren calls it the Light Side in The Force Awakens:
KYLO REN: Forgive me. I feel it again. The call to the light. The Supreme Leader senses it. Show me again. The power of darkness. And I will let nothing stand in our way.
Maz Kanata calls it the Light Side in The Force Awakens:
MAZ KANATA: I am no Jedi, but I know the Force. It moves through and surrounds every living thing. Close your eyes. Feel it. The light... It's always been there. It will guide you.
Supreme Leader Snoke calls it the Light Side in the first trailer for The Force Awakens:
SNOKE: There has been an awakening... have you felt it? The dark side... and the light.
Many of the Star Wars video games also call it the Light Side:
However it can also be referred to as the "Good Side", as Luke does in Return of the Jedi when speaking of turning Vader from the Dark Side:
LEIA: But why must you confront him?
LUKE: Because there is good in him. I've felt it. He won't turn me over to the emperor. I can save him. I can turn him back to the good side. I have to try.
It is called the "Light Side" of the Force, though "good side" is also acceptable. More often it is simply referred to as "the Force", "the way of the Force", or "the way of the Jedi".
The Force has a "Dark side", which feeds off emotions such as anger, jealousy, fear, lust, and hate, but the Jedi are only supposed to use the Force for peaceful purposes. The series' villains, the Sith, embrace the dark side in order to seize power. The Jedi's compassionate and selfless use of the Force has come to be known by inference as "the light side", although that term is not used in the films.
The Light Side is not the opposite of the Dark Side. That's a misconception from the sequels. The good side is the visible side of the Force, the kind one that can be shown to children, the Dark Side is the hidden side of the Force.