Memory cards - This is the most important! The footage that you cannot recapture is in there! Buy from a good place like BH.
Batteries - I have two original batteries and one OEM, the OEM is a piece of s*%t! Buy only original, you will get a time indicator and that will give you the opportunity to use the battery to the max and you will not be afraid that the camera will shut down. The original battery lasts double the time in my case.
