The end of The Hero of Ages. Also something of a Tear Jerker.
Sazed asking Tindwyl to stay in Luthdael.
Elend coming to rescue Vin at the end of the first book. Sure, this was before he Took a Level in Badass and as a result she wound up saving him, but it was the thought that counted- especially since Vin spent most of the book thinking that people were inherently untrustworthy. He may not have saved Vin, but together with the Inquisitor's revelation about Reen he just may have saved her faith in humanity. The ensuing scene is extremely heartwarming.
Vin"You came back!"
The Reveal at the end of book 1 that: Vin's abusive brother Reen never betrayed her despite his torture by the Steel Inquisition.. As the author notes in the annotations, Reen was not a good person but he did genuinely love Vin.
Kelsier's letter to Vin after his death: Farewell. I'll tell Mare about you. She always wanted a daughter.
Elend asking Vin to dance in The Hero of Ages. Doubles as a Crowning Moment of Funny when he pulls out a book, and then back into this category when it's the same book he was reading when they first met.