Persona 3, nothing says powerful like the most likable character saying goodbye, thanks to you, and actually cries for the first time.
Persona 4, haven't beaten it, but this forum alone is pushing me to finish it, for the ending...
Infamous 2, good/bad ending, yeah...
RDR, also yeah...
Shadow of the Colossus, so much love at the end...
No More Heroes, symbolism alone was tears of joy worthy.
I'm a sensitive guy, and I can safely say all these games made me shed a tear. But the award goes to Persona 3, I was alone in when I got to the ending so it was safe to cry like I was watching the end to Forrest Gump. Congrats Persona 3, and thank you Aigis for the most powerful final monologue ever delivered in gaming history.