Adult Gordie playing with his kid and kid's friend at the end of the movie. Considering he was ignored as a kid, it's nice to know he subverts this to his own kid.
Gordie and Chris's relationship in general. Though all of the boys are clearly very tight, there seems to be an extra special bond between Gordie and Chris. Considering what we know about both their family situations, they're pretty much all that the other has in terms of comfort and love. The fact that 30 or so years later, an adult Gordie who hasn't seen Chris for ten years, says he will miss him forever speaks volumes. They're pretty much brothers.
Hell, Chris in general. A beautiful boy from the wrong side of the tracks who houses a heart of gold inside him and a deep love for all of his friends, a boy who proves everybody wrong and gets out of his disadvantaged background and made something of his life.
The two flashbacks we see of Denny (Gordie's dead older brother) portray him as a Cool Big Bro — The first one is Denny giving Gordie his most prized hat; the second is Denny complimenting Gordie's writing and trying to get his parents to acknowledge it.