Hitomi version (Original): http://www.youtube.com/watch?v=7_-1X_N4c9s
Title: Heart no Kakuritsu (ハートの確率)
Artist: blue drops (main vocal Saori)
Source: Sora no Otoshimono: Forte (そらのおとしもの f)

This is the full version released some time ago.

Romaji lyrics:
saisho de saigo no SUKI
saisho de saigo no daiSUKI
unmei nante nani mo shirazu ni kimeta MIRAI dakara

kimi ni arigatou (kimi ni arigatou)
konna kanjou ga (konna KIMOCHI ga)
jibun no dokoka ni (mienai dokoka ni)
nemutteta nante (umareteta nante)

chikyuu o yusaburu youna chitei no MAGUMA mitai ni ne

HAATO ga me o samasu KOKORO ni hi o tsuketeku
NEGAI ga ugokidasu KODOU ni deatteku
saisho de saigo no SUKI
saisho de saigo no daiSUKI
unmei nante nani mo shirazu ni kimeta MIRAI dakara

kimi ga iru dakede (kimi ga iru dakede)
ureshiku naru kara (tanoshiku naru kara)
kimi ga warattara (sukoshi warattara)
issho ni waraou (watashi mo waraou)

kamisama aisareru to doushite konna ni atatakai no desuka

kimi no soba ni itai kimi no tonari ni itaiyo
asa mo hiru mo yoru mo haru mo natsu mo fuyu mo
imama de mita koto nai kono sekai no doko ni mo
nakatta youna PAWAA nakatta youna ashita

sora no shita baramakareta (LOVE LOVE LOVE LOVE SONG)
bokutachi no sonna mainichi wa (ALWAYS FOR YOU)
orokasa to setsunasa to (LOVE LOVE LOVE LOVE SONG)
HAPPII ENDO de dekiteiru

kimi no soba ni itai kimi no tonari ni itaiyo
asa mo hiru mo yoru mo haru mo natsu mo fuyu mo
imama de mita koto nai kono sekai no doko ni mo
nakatta youna PAWAA nakatta youna ashita
HAATO ga me o samasu KOKORO ni hi o tsuketeku
NEGAI ga ugokidasu KODOU ni deatteku
saisho de saigo no SUKI
saisho de saigo no daiSUKI
unmei nante nani mo shirazu ni kimeta MIRAI dakara

MAG.MOE - The MAG, The MOE.