Be sure to check out these versions
http://www.youtube.com/watch?v=gDbB4a1aec8 ("You" performed by 'Mion/Shion' Satsuki Yukino)
http://www.youtube.com/watch?v=POso2R-FX_U (You - Visionen im Spiegel)
http://www.nicovideo.jp/watch/sm21634836 (Live performance which WarriorKK kindly uploaded)
http://www.youtube.com/watch?v=vHnYEOeRLxo (With You Kizuna, sung by the voice actors of all the club members)
http://www.youtube.com/watch?v=R3K1uAhQ2x0 (You - Mirror Sky)
http://www.youtube.com/watch?v=dX6PDywtUNo (Violin & Piano Instrumental)