Pure emotion in games? These:
Half-Life 2 and Episodes 1 & 2: Very much all of Ep 2 was shocking and emotional, especially the end. But also simple moments in Half-Life 2 like seeing the distress of the people in City 17 and getting the crowbar for the first time.
MGS 3 & 4: The Metal Gear Solid games are full of emotional moments, but the ending to these two are particularly emotional. Seeing Snake in the state he's in after following his character over the course of games.
Shadow of the Colossus: Has to be played. It's difficult to convey in words alone.
Final Fantasy VII: Two moments: The point where Red XIII finds out the truth about his father and the "Aeris" scene.
Portal: Pure genius.
Deus Ex: The mood and atmosphere in this game is just fantastic.
Now, if we include anger then a lot of games would have to be included.
