Lungs give you a much bigger target and easier shot placement... and you can't eat lungs

Aim for the heart. If you're a little off, you still hit the lungs, anyway. Also, if the deer jumps the string, better chance of a hit if you aim for the heart. (imo)

A deer's front shoulder covers about 1/2 of the heart and when selecting where to shoot, I aim for the 2:00 position of the front leg - placing the crosshairs straight up the rear portion of the front leg and squeezing the trigger when they are about 1" below the top of the shoulder.

Dave has a excellent point, however, I always aim for lungs but aim low in case the deer ducks at the release, actually they jump but they will be crouching when the arrow arrives unless its a long shot or they catch movement of your draw.