Good emotional sidequest
I really liked the Normandy crash site side quest, as it was not about shooting or achieving an objective, but an act of remembrance and honor to the people who died on the Normandy and to the ship itself, which was reasonably emotionally important to the Shepard character and Joker, the ship's pilot.
My favorite part was Navigator Pressly's logs of his opinion of having aliens on the Normandy change to a point where he would "die for any of them". That, coupled with the Normandy memorial statue was an awesome and different addition to the gameplay of Mass Effect 2.