Well, I have this habit... I like to listen to music untill I fall asleep (my mp3 player has a timer function

)
Lately, I've been getting kinda tired of my "sleep playlist".
So: do you know any songs that are calm enough to make you relax?
I listen to Akino Arai's "Tsuki kara no inori to tomo ni" a lot... It's calm and powerful at the same time.