No. 13: Noble Team in Halo Reach
Every single member of Noble Squad gave his or her life in the hope of saving Reach from the Covenant invasion. From Jorge's valiant sacrifice at the onset of the attack, to Kat being shot down by a sniper, to Carter's suicide bombing of the Covenant Scarab, each and every loss was felt tremendously by those playing. Perhaps the most shocking of all though was the player's own sacrifice as Noble-6. Virtually the last man left standing on the planet, Noble-6 took on as many of the Covenant forces as he could as the ship containing Master Chief escaped Reach. It was quite a way to conclude a video game, and Bungie definitely went out on a high note.