My personal favorite sad scene has to be the fight in Rahxephon episode 19, where the main character is motivated by love for/desire to protect his childhood friend/love interest and so decides to grow a spine and use his giant robot, only to find out at the end of the fight that he actually killed her by destroying the attacking creature. What ramped the angst up to 11 were the messages scrolling across the signs on nearby buildings during the fight: "Please help me", "I love you" and then "Goodbye" right as he finished her off (which, of course, was the only message he saw).
The anime was mediocre as a whole, but damn, did it have some nice emotional scenes.
A close second has to be Elfen Lied. Pretty much most of the anime qualifies here, but a prize has to go to the flashback scene that the main character repressed from his memory, for good reason.
Saishuuheiki Kanojo was pretty much nothing but sad scenes, a number of which were done particularly well.
Bokurano has to get some sort of mention, though the crappiness of the anime takes away from its ranking.
And, of course, you can't have a discussion like this without mentioning Kimi Ga Nozomu Eien for pure emotion porn.
[Edit: Whoops, sorry, didn't realize I was necro'ing until after I posted.]
The anime was mediocre as a whole, but damn, did it have some nice emotional scenes.
A close second has to be Elfen Lied. Pretty much most of the anime qualifies here, but a prize has to go to the flashback scene that the main character repressed from his memory, for good reason.
Saishuuheiki Kanojo was pretty much nothing but sad scenes, a number of which were done particularly well.
Bokurano has to get some sort of mention, though the crappiness of the anime takes away from its ranking.
And, of course, you can't have a discussion like this without mentioning Kimi Ga Nozomu Eien for pure emotion porn.
[Edit: Whoops, sorry, didn't realize I was necro'ing until after I posted.]