mmm! kokia is reallyyy good. so is matsu takako. ohhh you have to listen to harvest songs!!! my favorite is "26:00"

I can fall asleep to basically anything, but when I want to just get in a relaxing mood, I usually end up listening to something instrumental or downtempo. A good chill/downtempo album usually does me just fine, atmospheric drum and bass is really nice too. It depends what sort of mood I'm in.

artists:
-Delerium
-Olive
-Photek
-LTJ Bukem

Oh my, I forgot to check this thread for a while XD Thanks everyone for the suggestions!
Now I'm into piano solos... I find them quite relaxing to sleep, while I don't like them much to listen daily XD

musics to sleep:
Mika Nakashima - I / Hitori / Carrot & Whip / aroma / Marionette / STARS / You send me love / LAST WALTZ
Maaya Sakamoto - Another Day In The Big Blue World / Grapefruit
Ayumi Hamasaki - rainy day / Two of us (and its remixes, trust me) / from your letter (and its remixes, except the pandart sasanooha ones)
Koda Kumi - RAIN / Ima Sugu Hoshii / feel / Your only one / Pearl moon
Crystal Kay - Eternal Memories ~Acoustic~ from Candy single