Lungs for me.

High forward lungs - has the greatest vascularity.
Straight up the leg - not behind the crease unless 1/4 away.

Steve

Although a heart shot Deer is dead on it's feet and will not go far. The last one I shot through the heart may have made it 35 yards.

I still would shoot for the middle of the Lungs. It's the Best Archery shot you can take as long as angle, etc. are correct.

Dan

Front and low on the lungs for me.

I aim for the lungs.

AirBags!

I've never completely dissected a heart, but do know it's a big muscle that's made up of arteries and if you don't hit a big enough artery the animal "can" run for awhile. Heck my buddy split a heart in half and the darn thing ran 150 yards!!!

Adrenaline if a powerful thing! Not to mention the will to live...

I like to hide in a ground blind and when a deer walks by I plunge a knife hand into his ribcage, rip out his heart, and show him his still beating heart just before he dies. then I spike his heart like a football and do an endzone dance!

If I have a bow I aim just behind the front shoulder and just a bit below center. Of course this (up or down) is dicataed by angle of the shot and whether the deer is alert or relaxed.

Lungs, bow or gun. That being said, if I could pin point the placement every time with bow, I'd go for the Femoral artery. I have never seen a deer bleed out faster than a femoral hit. Trouble with purposely going for that shot is too many things can go wrong.

I aim for the lungs as well.