A body falls freely from rest. Would the acceleration be -9.8 or 9.8 m/s^2?
Neither. You should get into the habit of always refering to the acceleration as a vector, unless you have already specified some particular coordinate system and are dealing with the components of the motion. I would say that the acceleration is (-9.8m/s^2)y-hat, assuming that the y-direction is defined to be 'up'.