This scene is from 14:31-19:26 in episode 14 (broadcast order) of S1 of The Melancholy of Haruhi Suzumiya. If you had watched it in broadcast order, this would have be a beautiful climax and end to the season which sent shivers down your spine. More crazy effects, classical music and stunningly good performance from both seiyuu Sugita and Hirano. Tanigawa, please write another book so S3 can be produced already!
Subs: [Deadfish] Re-encode
Torrent can be found on AnimeBytes, BakaBT or Nyaa.
Resolution: 1280×720
MAL: http://myanimelist.net/anime/849/Suzumiya_Haruhi_no_Yuuutsu
ANN: http://www.animenewsnetwork.com/encyclopedia/anime.php?id=6430
AniDB: http://anidb.net/perl-bin/animedb.pl?show=anime&aid=3651
MAG.MOE - The MAG, The MOE.