I think the other one is Hagane Miku. Fixed tag to reflect.

For future reference: the black-haired Miku is essentially Miku from either the standalone image PV or MMD PV for the song "Hope."

Not the happy peppy one, the depressing rock version.

from artist's comment in pixiv, it's for this song http://www.nicovideo.jp/watch/sm9809880 shinitagari (wanting to die)

also watch the PV version http://www.nicovideo.jp/watch/sm9937409